|
Ask any question, share your
knowledge, or offer your services!
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characteristics
of specific granite
| Q 2359: Verde
Butterfly versus Verde Lavras
for a kitchen countertop. The granite dealer/importer suggested
the Lavras because it is a denser, "less fragmented" stone. I like
the Butterfly precisely because of the fragmented look (slabs I looked
at had gold veining, black, and few burgandy spots). My question is,
"Can I go with my favorite, Verde Butterfly?" Or, would it be a bad
choice for a countertop? Karen, July 31, Reply |
| R1:
Dear Karen: If you accept the fragmentation, go for it! It's one of
the best materials for kitchen countertop that money can buy.
Maurizio, USA, |
| Q 2355: I've just ordered
peacock green granite
for my kitchen countertops. Did your lemon juice test and it wasn't
absorbed at all. Is this a good dense stone and should I seal it Thanks,
PK., July 30, Reply |
| R1:
Dear PK: My wallet bleeds while I'm telling you this: No, don't bother
sealing it! Maurizio, USA, |
| Q 2352: What do you recommend
for honed black granite
(Indian Premium)? Thanks, Susan, July 30, Reply |
| R2:
Never. Don't even think about it. Mike,
USA, |
R1:
Dear Susan: Recommend? Just get rid of it! It's only money, after
all, and your mind
welfare is worth more than that, I think! You can read several posting
about honed black granite (Indian Premium, or what-have-you) by scrolling
down this page and going into previous pages. They're all soaked with
tears!
Maurizio, USA, |
| 2326: We are looking
to use a black "granite" for a kitchen counter/ island sink top in
an Australian house we are building. Is the local product - Austral
black "granite" as reliable as "nero
assoluto" from South Africa, particularly from the
point of view of avoiding stains and damage (assuming that
it is not sealed)? Is there a big difference in cost between the two
stones? Ruth, Hong Kong. July 28, Reply |
| R3:
Dear Ruth, your mentioned AUSTRAL BLACK, is gabbro, similar to
NERO ASSOLUTO BELFAST from South Africa, but not such known. But you
have even closer stone of the type - ABSOLUTE BLACK or SUPREME BLACK
or SHANXI BLACK from China. I suppose this Chinese stone is cheaper
than imported stones. Daniel, Slovakia, |
| R2:
Dear Ruth: Run my little lemon juice test and you'll be able to tell!
Maurizio, USA,
|
R1:
Dear Ruth, Black granite is certainly a good choice for kitchen tops
because of their
high density, low degree of absorption, and absence of quartz. The
Australian "Austral" is a coarse-grained gabbro from Black Hill, east
of Adelaide with occasional whitish flares or clouds. This distinguishes
it from the higher-grade "Imperial" which should be more uniformly
black and is therefore commonly used for monumental purposes. Nero
Assoluto is a non-specific name given to black granites from a number
of places but more often than not denotes an origin from South Africa
and/or Zimbabwe. It tends to be finer-grained and closes well but
occasionally also has some textural variation. Given that both are
in the upper price range, have you considered some of the very high
grade, very fine-grained black granites from India and Shanxi (China).
Dr. Hans, Australia, |
| Q 2292:
We wish to put granite countertops in our new home, under construction.
We went to the slab yard our builder works with and found two very
different stones, both of which interest us. One is called "New
Venetian Gold" which is a light stone with some dark brown
spots/streaks. The other is called "Forest
Blue" which I believe is from South Africa. It's a
medium/dark green with blue flecks and looks very nice. Unfortunately,
we were unable to obtain scraps of these stones to test as you recommend.
Have you heard of these stones, and do you have any opinions on them?
I hope you don't mind a quick comment Michael, July 25, Reply |
| R2:
Dear Michael, FOREST BLUE is from South Africa. It is granite s.l.,
but petrographically looks like gabbro. Daniel, Slovakia, |
| R1:
Dear Michael:
As a rule, I always urge people to go somewhere else if they can't
get two of lousy pieces of scrap! New Venetian Gold is a good choice,
but does need to be sealed. I don't know much about the Forest Blue,
but I've heard that is quite dense. Anyway, I wouldn't dare to select
it without a piece of scrap to fool around with. Maurizio, USA, Expert
Panelist |
| Q 2284:
I am looking for granite for Island top. I like Baltic
Brown but am getting different answers regarding its
characteristics. Is it a hard granite? Does it have pits in it? How
absorptive is it? Would this be a bad choice in granite type? Could
you recommend better choice with similar color characteristics? Susan,
July 23, Reply |
| R1:
Dear Susan: I urge you to read the posting No. 2278 below by Monica
and my answer to it. Yes, Baltic Brown does have small pits and fissures,
like many other "granites". Maurizio, USA, |
| Q 2253: I am interested
in a stone called Azul Macauba to
be used as a vanity counter in a bathroom. One person told
me this was a granite, the other told me it was a marble. Which one
is it? Is it a suitable stone for a bathroom vanity counter? Can you
give me an idea of what I should be paying for this type of countertop
for a 58" counter, installed? By the way -- what is the difference
between marble and granite? Thanks very much. Napers, July 18, Reply |
| R2:
Dear Napers: I don't know exactly what kind of stone the Azul Macauba
is, but I do know it's neither, although it's traded as granite. About
the difference between marble and granite,Check the library in this
site. encyclopedia, or your stone retailer. They know a whole shipload
about stone all right!!! Maurizio, USA,
|
R1:
Dear Napers, Azul Macauba is neither a marble nor a granite - it is
a quartzite consisting mostly of quartz and a blue mineral called
dumortierite. It has a fairly high imbibition coefficient (rate of
water absorption) of about 0.6%, which means that it is very absorbent.
This means that any liquids like soaps and shampoos will be readily
absorbed. This results in a wet-look stain. If any liquids are spilt
on the vanity with a colour, the chance of discoloration is high.
But because the rock is quite hard and fairly resistant chemically,
common cleaning and/or poulticing methods will often work and not
be detrimental to the appearance of the stone. However, because it
is quite absorbent there can be other problems with this stone.
A recent investigation of conspicuous brown staining on the surface
of an Azul Macauba vanity top concluded that the 25mm thick stone
absorbed the oils in the glue used to bond the stone onto a vanity
cupboard frame made from customwood / craftwood. Whether the brown
stain came only from the glue or from a reaction between the glue
and the manufactured wood remains uncertain. There might also have
been an additional contribution to the problem by the housekeeper
who applied a solvent to the sealed surface and successfully but only
temporarily removed the stain. This solvent might have reacted with
either the glue or the wood thereby releasing more brown tannins or
oils. One important consideration is that despite being sealed with
a "high quality sealer" the solvent rapidly penetrated the stone and
dissolved/removed the stain. What does this say about the sealer,
or for that matter, about the stone?? Choose your application carefully
especially when it is one of the more expensive stone products
that you can buy. As for the differences between marble and granite,
there are many. Basically marble is usually a calcareous rock whereas
granite is typically siliceous. Marbles are generally quite soft (can
be scratched with a coin or a key) whereas most granite is relatively
hard and therefore scratched with difficulty using household items.
Being calcareous, marbles are chemically reactive to acids such as
hydrochloric acid (used in pools) and even relatively weak acids such
as acetic (vinegar). Marbles and limestone react with anything acidic
such as wine, carbonated drinks such as champagne, fruit juices, and
acid rain, and are even slightly reactive to drinking water
when the pH is lower than about 5. Granite is fairly resistant to
all acids except hydrofluoric acid (HF) which thankfully is not readily
available. Marbles originated from limestones (most of which are sedimentary
rocks) whereas most granites are of igneous origin (partly molten).
Dr. Hans, Australia, |
| Q 2194: I am interested
in a granite countertop for my kitchen and found
your website very useful. Although, I like light colored
granite, I am concerned it may get stained. Is the darker
granite less absorbent? I like St. Cecilia,
Gold Venetian, Verde Lavaras, and Atlantic Blue Granite.
Is there a listing of granites that are best for kitchens? Linda,
July 9, Reply |
| R1:
Dear Linda: Verde Lavras and Atlantic Blue are excellent choices.
Santa Cecilia and Gold Venetian are borderline, in my book.
None of them is a granite, of course! Maurizio, USA, |
| A 2162: We are interested in Santa
Cecelia granite. We have seen a sample which appears to
have a lot of purple dots that look like cigarette burns throughout
the granite. These dots seem softer than the rest of the granite and
are both porous and rough. Is this a common characteristic of this
granite? Claudia, July 5, Reply |
| R1: Dear Claudia:
Yes, it's the "nature of the beast" Maurizio, USA, |
| A 2157: Blue
Granite is the state stone of South Carolina. I was wondering
if it can be used for countertops? If yes, then how do I find a source?
Dobrenen, July 4,
Reply |
R1:
Dear Dobrenen: One learns something new every day!
Of course, I never heard about that particular stone; therefore I
have no answer to either one of your questions. |
| A 2047:
Could you send me information on cleaning, care and maintaining
Volga Blue granite? Also, what are
your thoughts on the quality of Volga Blue? Wayne, June 12. Reply |
| R1:
Dear Wayne: By the way, Volga Blue is indeed an excellent choice.
I love that stone!! Maurizio, USA |
| |
| A 2031:
I have had two homes with 'granite' in each and I am on my way to
the third. We want 'granite' again and were offered Rosa
Perrino, Santa cecilia, Ubatuba, Verde Ubatuba, Baltic Brown, and
Luna Pearl, all for the same cost. Are any of these real
granite or am I going to have a maintenance nightmare with them? That
is all I really want to know, you seem to have the 'right' answers
and I need some help! Sincerely, Dave, June 8. Reply |
| R1:
Dear Dave: Luna Pearl and Rosa Porrino are true geological granite.
(Actually, Luna Pearl -- a.k.a as Bianco Sardo is THE granite!) They
are absorbent, but their absorbency is limited and can be easily controlled
by applying a good-quality impregnator / sealer for stone. All the
other stones you listed are not granite, but, with the exception of
the Santa Cecilia, I consider them "better" than true granite for
all the intents and purposed of a kitchen countertop. They are all
quite dense and, most likely, require no sealing at all. I consider
Santa Cecilia "borderline" in my book. Its absorbency rate -- though
still controllable with a good impregnator/sealer applied several
times over -- is approximately twice as much that of true granite.
Maurizio, USA |
| |
| A 2028:
I am very interested in new countertops in my kitchen made of Barracuda
Blue granite. In your experience, what is the absorption
rate of barracuda blue? Also, I have seen one person note that it
is subject to fissures. Is this true? Should this be a matter of great
concern? Jim, June 7, Reply |
| R1:
Dear Jim: Never heard of that stone. Natural fissures are a common
occurrence on many a "granite" and usually don't represent a concern,
at least from a structural point of view. Maurizio, USA |
| |
| A 2014:
What type of stone is Giallo Veneziano?
Does it go under a different name? Is it a type of stone that
would absorb stains? How would you compare the Peacock
Green and the Ubatuba,
and Pocono Green which
one would you pick at first choice for a honey color kitchen with
dark brown trim? Something nice and I shouldn't have to worry about
staining? Please reply I am very confused what to do. Thanks, Sruli,
June 4, Reply |
| R1:
Dear Sruli: "Giallo Veneziano" is traded as granite (yeah, right!).
It's rather absorbent and will require some serious sealing before
using it. I don't know "Pocono Green", but the other two stones you've
listed are a much better choice than "Giallo Veneziano" from
a maintenance point of view. They are both much denser and require
no sealing at all. Maurizio, USA |
| A 1983: I'm
trying to find out from others who have Cambrian
black granite installed in their kitchens, how they like
it. Does it show dust and fingerprints easily? How about staining
and lustre? Scott, May 29, Reply |
| R1:
Dear Scott: Cambrian black -- an Anorthosite from Canada -- is one
of the best stones that money can buy for a kitchen countertop. It
will show dust and fingermarks like any other polished dark stone,
but it won't stain. Do NOT have it sealed.Maurizio, USA |
| 1910: We recently purchased
a new home and had Uba Tuba granite
countertops installed in our kitchen. I am struggling with routine
care as the countertop never appears to be completely clean after
use. It shows every fingerprint, drop of water and sponge streak.
In fear of damaging the surface, I have only cleaned with water (we've
only been in the house one month). I am seeking advice on daily routine
clean-ups, as well as, preventive maintenance. I've read that sealers/impregnators
(not sure the difference between the two) are not to be used on certain
types of granite. How do I determine if mine requires sealant or impregnator
and what kind? Any advice you can provide on the care of my countertop
is greatly appreciated. This is the first time I've had granite and
I want to take good care of it. Thanks, Renee, May 15. |
| R1:
Dear Renee: I can see that your fabricator -- as usual -- didn't supply
you with much intelligence about the subject of routine cleaning,
did they! Maurizio, USA |
| |
A 1906: We recently had
granite countertops (a color called 'Paradiso'
which contains a combination of black, grey/white and reddish brown
colors) installed in our remodeled kitchen and got the "we sealed
it at the shop" answer mentioned elsewhere in your archives. I tried
the lemon juice test on a piece of scrap and it appears to have passed.
However we have noticed 2 things that have us slightly concerned and
would like some expert opinions on.
First, although it passed the lemon juice test (no indication of absorption
or damage to surface after 2 minutes) I did notice some minor discoloration
to the darker areas of the countertop where a bottle of oil leaked
a bit and sat for a while. I intend to try the poultice to clear up
the spot but I am curious, does this mean that I should consider
an impregnator despite the lemon juice test?
Secondly, my wife in particular has seen other signs of apparent staining/discoloration
and is concerned about the appearance of pores in the surface (tiny
pits that can only be seen when viewed nearly edge on with light reflecting
off the polished surface.) Is this also an indication of a possible
need for an impregnator.
We are complete novices and are not extremely
confident in the answers we may get from our manufacturer after the
response from the fabricator/installer and I appreciate the honesty
and integrity I have seen in the responses on your site. Thanks in
advance, Ray, May 15. Reply |
R1:
Dear Ray: If it did absorb oil, then it does need to be sealed with
a good-quality impregnator. No matter what, however, it's never a
good practice to leave oil or butter or margarine sitting on the countertop
for a long period of time.
The pits are natural occurrences and you shouldn't worry about them.
No, an impregnator / sealer won't do anything about them. Maurizio,
USA |
| A 1888:I was reading
with interest your answer to a query about nero
assolute granite. I am just about to order some granite
for a kitchen island. I'm leaning toward the Nero Assoluto for two
reasons. First, I like the look of black granite. Second, I can't
afford to do the rest of my counters at the same time so I thought
a relatively grainless granite would be easier to match that a more
elaborate granite. However, reading the Q&A banter, it seems the absolute
blackness makes staining more noticeable. Is this a common problem?
I would also like to know whether fading is an issue. I have read
somewhere that suppliers have been known to dye granite to make it
blacker than it really is. Steven,
May 15.Reply
|
R2:
Dear Steven: Nero Assoluto (the real
thing) is a Dolerite from South Africa. Nobody can
"doctor" it with the application of a dye. It's an excellent choice.
Other black "granites", mostly Gabbro, are excellent too, e.i., Black
Jet and Black Galaxy from India (no "doctoring" possible on those,
either!).
But, while the criteria of your choice is quite smart (a solid black
stone is easy to match even years down the line!), your fear is not
without ground. Unfortunately, some "black granite" are, in fact,
"doctored". To find out if a "Black Absolute" has been "doctored",
rub a clean rag soaked with acetone over a scrap piece of it. That
will tell you for sure!! Maurizio, USA |
R1:
Dear Steven, Nero Assoluto is both
a generalized and specific latin name given to black
granites. The anglicised version is absolute black. They have a number
of major sources - South Africa, Zimbabwe, India, Sweden, China, and
to a lesser extent Australia. Most fine-grained black granites are
good quality - because of their high quality of polished finish, paucity
of deleterious minerals, lack of alteration, a lack of mineral orientation,
an isotropic
structure, and few micro fractures. These properties combine to give
the rock high strength and a low imbibe coefficient (absorption) -
ideal for kitchen bench tops. You can't do better than a rock of this
type. Sure, it makes spillages and dirtiness more noticeable - but
that is not staining.
You do not have to seal good quality black granite! And be aware that
some doctoring does go on in the stone trade. The application of certain
oils and other products can darken the stone temporarily and make
it look more impressive. However, such treatment will lead to a fading
within weeks or months. This artificial treatment can be checked by
the application of
acetone (or similar volatile hydrocarbon solvent) and a bit of elbow-grease.
If some colour shows on the white material that you have used go elsewhere
for your granite. Also be aware of the resin treatment of certain
granites. I have just investigated and described this type of rock
and Black Galaxy from India to which resin has been applied. Check
the clarity and sharpness of some reflections (e.g. trees). I don't
like it but then some consumers will. Incidentally, most of the fine-grained
black granites are dolerites that have been contact metamorphosed
and many have weird and wonderful reaction phenomena under the microscope.
Dr. Hans, Australia |
| A 1885: We need to redo our kitchen
and bathroom countertops. We have seen granite at called
Baltic Brown. After reading your very informative
website I am still confused. Are you saying that if it is a true granite
and passes the lemon test that it will not need impregnator or a wax
sealer? I do not want to be a slave to my countertops. Please give
an answer. THANKS, Ann, May 15.
Reply |
| R2: Granite
is most excellent. The only acid that affects it is hydrophoric acid,
this name is wrong, it sounds like that although. Anyway you mostly
will not be working with this acid on the countertops. Granite is
very porous, Solvent based Impregnator will rid you of staining in
most cases as long as you are diligent in wiping up spills and moisture.
Testing for adsorption every 3 to six months. Pour about an ounce
of bottled water in different work areas of the counter top. If it
stay puddled there for ten minute the impregnator is still working.
If it starts absorbing the water, hand scrub the countertops with
a neutral detergent, let the granite dry for at least 24 to 48 hrs.
and impregnate again with the same product. Most of the time the impregnator
last quiet a while and by doing these test will in most cases keep
you ahead of the staining problems. Nothing say class and beauty like
granite. Randy, USA. |
| R1: Dear
Ann: Baltic Brown will be your faithful slave for the rest of your
natural life, not vice-versa!! No sealer needed (here we go, I lose
another sale!!). Maurizio, USA |
| A 1870: Hi- the
info you provide on the website is great. I did the lemon
juice test on a tan/beige colored "granite" that I was told
was from India and called Golden Viera
(?) It didnt stain immediately but did after 30 secs or a minute...
In the granite yard the piece was outside and had huge water stains
on the bottom from the rain, but the granite man said that's because
it wasnt sealed yet It took me MONTHS to find this color/design and
I love the look but don't want a high maintenance countertop, esp
since I cook alot and have kids that dont clean up after themselves
:) Will the sealer be the answer, and how and how often do I seal?
Is there any other very neutrally beige/tan/taupy granite that has
a look of marble that you know of. Thanks, Darlene,May 15.Reply
|
R2:
Dear Darlene: The result
of the lemon juice test the way you report it indicates that your
"granite" is within those that can be controlled fairly well with
a good-quality impregnator sealer. You should go for it.
How often you should have the sealer applied depends on the make of
the sealer. Some manufacturers recommend to seal every year (in this
case we're usually dealing with Silicon-based sealers). Some others
will tell you every 3 - 5 years (Silane-based sealers). Others, every
15 - 20 years (Ester-epoxy based sealers, my very favorite). The latest
generation of sealers (Fluorocarbon-based) promises to last a long
time, too, but that type of products are too new to venture any reliable
frequency of application. Once you start with a sealer is advisable
not to change brand for future applications: There could be compatibility
problems. Maurizio, USA |
| R1:
Dear Darlene: There
are a number of beige-coloured granites on the world market. Many
are coarse-grained and a bit weak (e.g. Venetian Gold), others have
spots and alteration products, and some are swirly. A very boring
(uniform), fine-grained granite is Brisbane Beige from Australia.
Dr. Hans, Australia |
| A 1855:I
have just recently put down a Kashmir White
floor down in my kitchen, and am getting Kashmir White countertop
and backsplash. At looking at this website, it seems like I haven't
made the best choice. Please advise how to clean the countertop and
floors. I have seen you need to use soap and water. When you say "soap",
what kind of soap are you referring to? Also, I don't believe my floors
were sealed, and they have a brownish color in some of the tiles?
What should I do about this? Thanks, Baine, May 14. Reply
|
| R2:
Dear Baine: Let me start out by saying that I feel deeply sorry for
you. If you still can get out of your deal about the countertop, by
all means DO THAT. No, you do NOT want to use soap (of any type or
brand) on a polished stone surface. It will leave a film that will
keep accumulating until it becomes plain, unsanitary scum. That said,
even if with little hope, your "granite" has to be sealed
to death with a good-quality impregnator sealer (please, leave my
own sealer out of the picture. I really don't care to deal with those
kinds of stones). Maurizio, USA |
| R1:
Kashmir White is an extremely porous material. For the floor you will
need to get a polymeric finish for it and reapply frequently, I don't
consider this something you can do your self. Contact Maurizio
for instruction and advice. If it is not too late. select another
material for your kitchen counters. Regards, Steven, USA |
| A 1851: I
am building a new home and would like to use granite counter top in
my kitchen. I was shown a sample that was marketed as Chestnut
Granite from India. I researched further and now believe
it may be Sapphire Brown.
Could you tell me if this is possible and if its is a good choice
for a top. Will it need to be sealed? Also when you do your lemon
test should it be done on the raw material or can you use the sample
that is polished. Thanks. Mark, May 14. Reply
|
| R2:
Dear Mark: The lemon juice test must be run on the polished side.
Maurizio, USA |
| R1:
The sapphire brown is a good product. Test the polished side. Good
Luck, Steven, USA |
| A 1830: email me relevant
information, about natural stone quarried in San Antonio, TX
& Austin, TX or surrounding areas. Types: water erosion &density
factors that would pertain to pond & fountain or water falls.
Yrubn, May 14. Reply
|
| A 1826:
I'm building a new house. I just had my countertops installed this
week. We chose Labrador Antique.
It has great shade, colour, etc.. But I've found a rather big flaw
on the island slab. It's a odd shaped black spot which is not polished.
It's dull looking and rough. It looks similar to coal. Have you seen
this before? Should I ask for a price reduction?? It's about 1 inch
long by one half inch wide. Looking at the rest of the piece with
a reflection, there are certain tiny dots (dimples) that are noticeable.
Should the entire top be perfectly smooth without any defects? Mark
May 14. Reply
|
R2:
No this may not be a flaw. Labrador Antique has these inclusions.
If you get a light and shine it on the black spot from various angles,
do you see a blue or green crystal reflection?
Regards, Steven, USA |
| R1:
Dear Mark: Without
actually seeing it, it's hard to make statements, but my educated
guess is that dark dull spot in the middle of the slab is not natural.
I suspect that it's some sort of filler that had been applied in the
factory (not at the fabrication shop). Should you accept it? ... There
are no standards on how picky one should be, are there! ...A small
reduction in price would seem more appropriate. Again, remember, all
the above statements are olny assumptions. About the other flaws you
indicate, they are typical of many a "granite", including the one
you have, which, by the way, is an excellent choice. Maurizio, USA |
| A 1764: I am interested
in Grigio Perla (Italian granite) for kitchen countertops.
How does this stone perform in such an application? How easily does
it stain, etch, crack, chip? how can I go about finding it? Thanks,
Caroline. April 27. Reply |
| A 1747: I am ready to
buy granite for my countertops and I know I want a green.
My appliances are stainless steel and my cabinets are Golden
Oak. I was looking at the Uba Tuba,
however it has a lot of black in it. Is there a green granite with
gold flecks and little to no black. I want them to appear a jade green-
not black. My biggest problem is that you can't view the samples.
The internet pictures all look different or it is too small to get
the full effect of the stone. I would appreciate any advice. Mitchell,
April 22. Reply |
R3:
Mitchell, It is such a coincidence that I am also deciding between
Uta Tuba and Verde
Butterfly for my kitchen counter top. The cabinet is made
of beech and the color is golden yellowish color. So the color is
same as your cabinet
I was wondering what you have decided. I am thinking of going with
the Verde Butterfly. It has more gold and white speckles. The speckles
are really big. It looks really beautiful. The Uta Tuba has smaller
speckles and the color is darker. Thanks, An, USA. |
| R2:
Ubatuba is by far the most popular green granite in use today. To
be fair, you should view the slabs that your fabricator has in stock
or will be purchasing. We have had this material range from almost
black with a lot of gold to olive green/blue with no gold. A related
granite is Verde Butterfly or Mariposa which is also from Brazil.
It has a larger crystal and is a deep green with gold. Good luck.
Lynn, USA |
| R1:
Try Verde Butterfly also known as Verde Pavao. Regards,
Steven, USA |
A 1731: I
just spent the whole evening reading your advice to homeowners about
various aspects of remodeling.
I am about to replace the old kitchen counter with a new one made
of either granite or silestone. My esthetic choice is granite, although
I do worry about stains that could become permanent. How about
UBA TUBA, DAKOTA MAHOGANY, ALMOND MAUVE?
– are they true granites or are they reasonably resistant to penetration?
What might be some good choices (dark color, no waves) that are least
porous but won’t break my pocket book? Helen, April 19. |
| R2:
By maintaining your granite with a good penetrating sealer (impregnator)
you will minimize staining. The darker materials you mentioned, Ubatuba
and Dakota Mahogany, will by their dark nature show very little discoloration
that comes from oils. Almond Mauve, on the other hand, will show the
darkening with time that use of cooking oils and even oils from your
hands will produce. Lynn,
USA |
| R1:
All your listed choices will provide a good counter. The Almond Mauve
will require an impregnator. Regards, Steven, USA |
| A 1727: I have on order
a large granite countertop. I chose and specified Belfast
absolute black. I selected a slab at the importer
which was classified as Absolute Black.
The fabricator picked up and delivered Zimbabwe
Black. They are pushing that these are in fact the
same type stone and any absolute black, which Zimbabwe classifies
as, can be substituted. That absolute black stones are so uniform
they don't need a "selected stone" to fabricate. In fact the Zimbabwe
is the premium of these stones. I feel I can see a difference in depth
of color between Zimbabwe and the "absolute black" I selected. I am
hesitant to enhance the color or use a colored polish, I want as maintenance
free a solution as I can get. Any suggestions and can you
clarify the difference between absolute black stones. FYI due to a
great deal of stripped fading in the first stone that was delivered,
this is actually a replacement countertop. Denise. April 18. Reply |
| R1:
Generally I find the Zimbabwe version grayer than the Indian version.
If you don't like it don't accept it. Further, if you have had trouble
once, don't repeat the mistake of allowing the slab to be "doctored".
Regards, Steven, USA |
| A 1726: I selected Bethel
White granite from a supplier in Vermont for application
as a slab countertop with 12 inch tiles (Bethel White granite) as
the backsplash wall application. The slab has a series of small rust
spots and I am hesitant to approve this material for delivery. The
supplier suggested that I change to Impala
Black slab granite and tiles (from Africa). I need
to decide and I am concerned about the rust spots on the Bethel White
and use of the granite tiles behind my professional, gas-burned cook-top.
My intention is to run the tiles from the top of the counter to the
ceiling. My granite knowledge is limited but I'm trying to learn -
quickly! Can anyone provide some perspective for me? Lyenne. April
18. |
| R2: Well, It
seems to be a black versus white quandary. If you don't like the white
then don't approve the slabs or tiles. If you don't have a problem
with Impala Black then I say use it. It is a very good stone for counters
and splashes. Regards, Steven, USA |
| R1: Bethel
White has, according to my knowledge, Pyrites which can rust with
age. It has to be treated and maintained regularly. I can suggest
a product without prejudice. Thomas, South Africa. |
| |
| A 1719: I visited a stone
merchant to pick out my granite slabs. I saw a slab named Santa
Cecilia, took a sample home and did the lemon juice test.
I don't "think" I saw any problems, but was wondering if you could
offer any comments on the stone. Thanks, Laura, California, April
17. Reply |
| R1:
It is a popular product in the US. It will require the application
of an impregnator. Regards, Steven, USA |
| A 1714: Hello Maurizio,
I'm doing your lemon test right now on my Giallo
Veneziano sample. I'm not sure if this sample
has been sealed or impregnated. The granite seems to darken
very slightly, but the lemon does not get absorbed into the stone
for quite some time (25 minutes and still counting). If I understand
the test correctly, this should be a good choice. Can you please
confirm? Thanks, Teresa, April 16. |
R2:
The Giallo Veneziano is absorptive. It will need the application
of an impregnator.
Regards, Steven, USA |
| R1:
Dear Teresa: If it darkens, it means that it's being absorbed. In
my opinion that particular stone is borderline, but - I must admit
it - my standards are quite high! If sealed properly, you will enjoy
your stone for years to come. Go for it! Maurizio, USA |
| A 1706: Hi, I'm thinking
of using Madura Gold
or Madura Gold Light
granite for my kitchen countertops. Do you know if these are
low absorbency granite, or even if they are a true granite? I don't
have a sample so have been unable to perform your lemon test.
Thank you for your time, your expertise, and your informative website.
Melinda, April 14. Reply |
| R2:
Dear Melinda: No they are not granite. If you can't get a sample to
run the lemon juice test, go to another fabricator. Maurizio,
USA |
| R1:
Dear Melinda, MADURA GOLD from India is migmatite - metamorphic rock
with wave structure probably composed from quartz, feldspar, micas
and limonite. I think it is suitable for countertop. Daniel, Slovakia |
| A 1699: I have intentions
to buy absolute black
for garden tables and received samples from India. This in polished
and honed version; I did the test with lemon and it gives spots, but
not with oil, coffee and tomato extracts. I did not have the intention
that I gives much dirty spots and is easy to clean. Is there a
difference in Indian or South African granite? What kind of oil
can I use and is there another grey or black granite I can use? What
kind of stone is most used for garden tabletops in the USA? Do you
know Belgian hardstone? Very nice for garden tables, but sensitive
to dirt so I am looking for granite as nice as Belgian
hardstone, but better quality. Greetings, Marc, April
13. Reply |
| R3:
In South Africa we have Rustenburg or also called
Impala granite which is as well known as the Carrara
Marble all over the world. The Rustenburg granite is an excellent
material and does not have to be sealed. The material is available
from our quarry. Thomas. South Africa. |
R2:
Dear Marc: Well, which one produced spots with lemon?
For all I know both the South African and the Indian (at least the
one that I have in mind) are equally good, although geologically different,
and neither should be effected by lemon juice, unless ... they have
been "doctored". I've seen such a "nice" fraudulent procedure done
mostly on Black Zimbabwe, but it is not to be excluded that it's been
done on other "black granites" as well. Black Zimbabwe (which, as
the name itself indicates, is not from South Africa) is actually a
dark grey stone and, because of that, not very "sellable" as darker
stones. So, here comes the unscrupulous slab manufacturer that applies
a black "shoe-shine" sort of makeup to "make" the stone black. Acids,
will remove that makeup, hence the "etchings" which is not on the
stone, but on the applied-on finish. If one removes completely such
finish and accept the natural lighter color, then it's a very enjoyable
stone.
None of the black "granites" I know of need to be sealed. So, the
reasons fo the reaction to the lemon juice could also be the consequence
of the presence of an impregnator-type sealer that has no business
being there, and shows damages because it never got a chance to be
absorbed by the stone (they are all very dense.)
The other liquids that you tested confirm that the stone doesn't need
sealing. Maurizio, USA |
| R1:
Dear Marc, The main difference between the two black granites is price.
You can use any other dark grey or black granite for your intended
purpose - all will need some maintenance if left out in the garden,
especially under trees. For additional maintenance you could try a
honed finish. As for Belgian "hardstone" - remember that
beauty is in the eye of the beholder. If that beholder is a bit blind
then many things are beautiful. And as for the oil that you could
use try the extra virgin variety. (Dr. Hans), Australia |
| A 1579: What can you
tell me about the quality (reputation) and care (and anything else
you know) of "Tiger Skin"
granite? I saw this and had to have it for my kitchen. Gina, March
22. Reply |
| R2:
Dear Gina, your taste is excellent for TIGER SKIN is a beautiful stone.
This gneiss from India is hard, resistant material. Losst of lustre
can be in black streaks with mica accumulation, but it is a feature
of this stone type. Daniel, Slovakia. |
| R1:
Dear Gina: I've heard of it, but never saw it (or maybe I did, under
another name!). The only advice I can give you is to use my little
"lemon juice test", then draw your own conclusions. Maurizio, USA. |
| |
| A 1562: I am considering
Avanza countertops for my newly
remodeled kitchen. I am not a friend of Granite - since the colors
are not what I am looking for (white with silver flecks). What kinds
of things do I need to watch March 20. Reply |
| R1:
Sorry never heard of it. Many companies private label their stones
to make identification difficult. I am sure you understand that this
is a stone industry site, not Avanza ask them how to take care of
it. Regards, Steven, USA, |
| A 1501: I need information
on Gold Vyara. Is it a hard or
a porous granite? Is it a good maintenance choice for kitchen countertops?
Tom, March 8. Reply |
| R2:
Dear Tom: Hard and porous are not related. For the suitability of
the stone you mention as a material for a kitchen countertop, run
my little "lemon juice test" (on the side bar), then draw your own
conclusions. Ciao, Maurizio, USA |
| R1:
It is a porous stone and will need a good sealing process. It does
tend to have fissures and hairline cracks but that is the beauty of
the stone. I typically fabricate jobs using this material in the 8
- 10 slabs range per job. Customers love the softness and unique look
of the stone. LkCmbr,
USA |
| A 1499: I am trying to
get information about Juparana
Florenca for my kitchen countertops. Is this a good choice?
Thank you. Debbi, March 7, Reply |
|
R1:
Dear Debbie: Run my little "lemon juice test" on it (see side bar),
then draw your own conclusions. Maurizio, USA
|
| A 1475: I
am considering using "Azul Aran"
(aka "Blue Paradise")
for my kitchen counters. However, I heard about it being prone
to rust in water situations, because of metal in the stone. Is
this a concern in the kitchen (versus the bath)? Will sealing avoid
any risk of rust? No matter how careful you are, stuff happens (wet
glass left overnight; leaking faucet). Ed, Feb. 26. Reply |
| R1:
Azul Aran has gotten some bad press. It is a pretty stone and I would
judge it on a block to block basis. If you leave a glass on the counter
and it leaves a ring this small amount of moisture would not rust.
I am not sure (Dr.Hans probably knows) but I don't think it is iron
in the stone. I believe that some of it has pyrite and this can oxidize
and be seen as rust. If you have the stone impregnated with several
coats of properly applied impregnator it would probably prevent any
oxidation. Regards, Steven, USAReply
|
| A 1250: I could have
an order for installation of Yellow
St. Cecilia. I am doing a job near Boston, MA, USA.
Owners only concern is gritty or flaking of granite
counter for cooking surface. The problem is they have friends, who
have this stone and when you run your hand over it your hand
is full of what feels and looks like sand. This counter
does not seal or clean and still flakes. Note this is not a
true granite. I need to know if this stone is ever going to
stop flaking. Would like to give more info, but tell me what
you need to know? Mike
Dec 11. Reply |
| R4: The areas in
this stone that flake are the oxblood color spots. They are
significantly softer than the the other parts of St. Cecelia.
There are some varieties that have fissures and some surface
pitting. This product is very absorptive. Consequently if they
cook a lot, steer them into a different stone. Steven, USA
|
|
| R3: THE REASON IS THAT THE STONES WERE UTILIZED
SLABS FROM BLOCKS OF THE UPPER PART OF THE QUARRY, NOT PERFECTLY
"STONED". THIS PROBLEM IS EASILY SOLVED WITH EPOSSIDIC RESIN
ON THE SLABS BEFORE POLISHING, BECAUSE THE RESIN CLOSE ALL THE
MICRO HOLES AND YOU HAVE A PERFECT SURFACE AFTER THE POLISHING.
THIS IS THE NORMAL WAY WHEN YOU HAVE MATERIAL WITH SMALL HOLES
ON THE SURFACE ; OUR SLABS DO NOT HAVE THIS PROBLEM, BUT IF
THE CUSTOMER WANTS WE CAN DO IT, THE PRICE OF THIS PROCESS IS
$ 15.00/SQ.MT. REGARDS. VINICIO, Italy, |
| |
| R2: This granite should work for you in the
kitchen, After installing clean & seal. Atkin, USA |
|
| R1: Quite honestly, I don't understand
much your question. Maybe you were thinking at the cost of wiring
your message, where they charge you by the number of words!
Anyway, if the grading of the slabs is good, you shouldn't have
any problem with that particular stone. Keep in mind that's
not a true granite, and it does require massive doses of a good-quality
impregnator-type sealer. Maurizio, USA |
|
| A 1176: Dear Sirs, Is Lillet
granite slightly porous? Is this stone known under different
names like "Alba Roso"
or "Sunset Rising"?
Have you ever heard of these types of granite? With best wishes, C.
Francet, Nov 10. |
| R2: Dear Francet: Mmmmmmm .... "Sunset rising" .... That's
a good one, all right!! No, I don't know. Run the lemon jiuce test
to find out yourself about the absorbency and suitability (as material
fo a countertop) of that particular stone. Maurizio, USA. |
|
| R1: Dear C. Francet, Lillet granite is slightly porous. Alba
Roso or better Rosso Alba is Iranian marble, Sunset is granite from
USA, maybe granite from India, Sunrise is Indian granite. Daniel,
Slovakia. |
MY GRIPE: I am an end-user who contracted for the
delivery of some Italian granite tiles, 60 mm x 60 mm x 3/4 worth some
$ 80,000 in various colors, among them Blanco
Pero or Blanco Pera. Delivery
is almost complete. However, recently I have had reason to suspect
that the granite tiles supplied to me did not come from Italy but from
China. I have heard that this is happening particularly in Asia. Could
you tell me if you know any quantitative and qualitative tests that I
can use to determine if I have been duped? Would you also have an
expert in the Asian region? Ayette, USA, Reply
R4:
I
think this is not BLANCO PERA but Spanish granite BLANCO PERLA. Daniel,
Slovakia
R3: The only quantitative
method to use is to check the physical properties of the stone such as
density, absorption, etc. There are a group of stones from the Carrara
and Massa section of Italy. When you buy such quantity, you may want
to speak to the quarry to see if they remember the order. You probably
want to use the Italian word for white-- Bianco, however. Ask what grade
of marble you receiving is i.e. 1 - 4 and what group it is from. Expect
the Italian variety to be Group A (very sound). Best of luck! Steven,
USA.
R2:
It is very simple to find out if what you are supposed to have is what
you really do have. A petrographic analysis is straight forward
and fairly cheap method of characterizing every rock. It is a bit
like DNA testing in that it is extremely unlikely that rocks from two
different continents are identical in their mineralogy, texture, and structure.
However, it does have to be done by a specialist - preferably one in the
stone game. The "perpetrators" of any possible substitution might
come back and say that the petrographic analysis is invalid because of
natural variation in natural rock tiles. This argument does not
stand up scientifically. If any
argument got more serious then there are many other somewhat scientifically
more sophisticated methods for fingerprinting rock, e.g. isotopes.
So, all you have to do is get small pieces (20mmx10mmx10mm, or a little
bigger) of the stones and have them analysed. The hardest part is
to get someone reputable who could supply you with a small piece of broken
tile of the two genuine European stones so that they can be used as reference
material. Hans, Australia
R1: A Spanish name for an Italian
"granite" that's perhaps coming from China!... That gives a brand new
meaning to the definition of international trade! I have no answer to
your question. You may want to try with some University (Pennstate, maybe).
All I can tell you is that Italy is, by far, the largest producer of dimensional
stone in the entire world. The fact is, however, that the stones coming
out from Italy are not necessarily quarried in Italy. Italian producers
buy blocks from just about all over the world, they process them into
slabs and / or tiles, then off they go! You may want to consider demanding
the importer to disclose the exact location of the quarry for you. If
they tell you the quarry is, in fact, in Italy, let me know where and
I'll find out for you if they're telling the truth (I still have strong
contacts over there!) Ciao and good luck! Maurizio, USA.
A
1079: I am getting conflicting information regarding the prevalence
of fissures in Lagos Azul slabs. One
supplier tells me that they are customary, and, of course, his slabs have
a lot of fissures and pits. Another supplier tells me that Lagos Azul
is generally very solid, lacking fissures. Both suppliers' slabs
have what appears to be black, tar-like, filler material, but both suppliers
offer different stories about this material. Lastly, how do you
feel about using Lagos Azul for kitchen counters? If you think it’s
a bad idea, can you recommend a natural material that would complement
Lagos Azul floor tiles? Thank you, Tom, USA,
August
28, Reply
R1: For all I know Lagos Azul has a lot of unofficial grading.
Some slabs are more solid than others. It much depends on the purchasing
ability of the fabricator, and how much he's willing to spend. I never
had the opportunity to test such material for absorbency and resistance
to acids. But you can run a couple of easy tests yourself. Get a piece
of scrap slab, take it home and spill on it some lemon juice. You need
to check two things:
1. Does the juice get absorbed right away? (Producing dark spot within
a few seconds of its application). If so, you know that the material is
extremely absorbent. I personally wouldn't want it in my kitchen, if that
were the case. But then, we're Italian and both my wife and I love to
cook a lot!
2. If it doesn't absorb readily, then you're
in good shape as far as absorbency is concerned: A good-quality penetrating
sealer will take care of that. After approximately a minute or so, wipe
the lemon juice dry. If it left a dull spot where it was sitting, then
you do not want that material in your kitchen, floor included. If not,
it's OK. Good luck and Ciao, Maurizio, USA Contact
Id 1003
USA: Can you tell me if Pietra del Cardosa
is granite? How will it hold for a kitchen counter top? Will
need special maintenance? Aug 23. Contact
R1:
Pietra del Cardoso is Italian grey sandstone, not suitable for countertop
because it is not polishable and contents calcite. Daniel, Slovakia
A 1051: Name
It: I have often heard that India
Black was best for art work on granite as it had a very fine
grain and therefore the letter or image would give the best results for
monuments. However, some of these black stones appeared to have
water marks running down the polished surface. Is this suppose to
happen on India Black or is this likely a lower quality of black granite?
Any info would be appreciated? Calvin, USA, July 21. Reply
R1: That's a lower
quality. The best Indian blacks do not have this problem. See
the Indian granites in our Stone Album. FindStone.
I went to the Indian
granites and I thought "India Black" was a particular one in your photo
album. This is a name that I have seen listed with some dealers
but perhaps this is a name they use to call all Indian Blacks. And
as you said in your earlier email some are of lower quality resulting
in the dyes running out over time. While there were several named
blacks, which one is the finest grained one for use in monuments where
this bleeding is less unlikely to be present. Is it Ratnasila Black?
Is there some kind of grading system in place one could look at to see
photos of the various grained stones (course to fine grain granite).
Many thanks, Calvin, USA,
R2: Best thing to
do would be to put your requirement in our site by filling the 'Put Advertisement form'. The lower quality
ones are sometimes darkened chemically by unscrupulous exporters. If you
see the articles in our Library (I think one called Defects) you will
understand better. There is no grading system. Those in the industry know
the different areas from which black granites are quarried and they know
the quality from each such area. The
best, for example, is from Kunnam in India and is thus known as Kunnam
Black. FindStone,
A
1049: Is the Dynamic Blue as green as it looks on our computer.
Is this a good countertop material. What other blue granite besides
blue pearl do you recommend that would match an azul boquira porcelain
floor? Tim and Kay, USA, July 9. Reply
R1: Dear Tim &
Kay, I recommend you Brasilian blue material which match your porcelain
floor, but this material is changeable and expensive. They are named:
AZUL IMPERIAL, AZUL BOQUIRA or AZUL MACAUBAS. There are some hard blue
materials like AZUL BAHIA or BLUE KING. They are less changeable but there
is possibility of chemical damage - color change. Daniel, Slovakia
Q 973:
What are all the minerals of Kazakhistan and exact location? Kamal,
USA. May 9 reply
R1: The properties of fine grain black "granites' usually don't
vary greatly in different directions so they don't really have a "grain"
direction like wood. Regards, Jim, Australia.
A 954:
Could you tell me the main minerals that make up Absolute
Black? Simon, Australia, April 6. Reply
R1:
I
suppose the mineral composition because of great similarity with the materials
(gabbros - dolerites) from South Africa, Zimbabwe and Sweden pyroxene
and feldspar (Ca-plagioklase). The next not main minerals may be or not:
magnetite, olivine, apatite, quartz, chlorite, biotite, amphibole, alkaline
feldspar.
Daniel,
Slovakia
A 929: What
is the composition of black granite?
What minerals are present?, Sollacks. USA, Feb 21, reply
R2: Black granite isn't really granite. Its correct name
is Norite.
A typical composition of
5% K feldspar
50% Na feldspar
30% pyroxene
8% biotite
5% opaques
2% other
Regards, Jim, Australia
R1: Dear Sollacks, There are many ways of answering this one
depending on what sort of composition you mean (chemical, normative, isotopic,
etc). You will find many analyses of black granites from all over
the world in "Journal of Petrology" and "Contributions to Mineralogy and
Petrology" but you will need to go back to the early volumes (1960's -1970's)
to get the best information. You probably only want to know the
mineralogical composition of black granites. Most black granites
(a term restricted to the stone trade) consist of 3 basic minerals - calcic
pyroxene, plagioclase feldspar, and an iron oxide. The pyroxene
typically occurs in quantities of 20-35% and provides most of the dark
coloration. The feldspar is mostly a calcium-rich variety and typically
occurs in quantities of 50-65%. The black iron oxide (titanomagnetite)
or iron-titanium oxide (ilmenite) commonly constitute about 5-8% of the
rock. However, typically there are also small amounts of other minerals
in most black granites including amphibole (e.g. hornblende, kaersutite)
and a dark mica (e.g. biotite, phlogopite) and there is sometimes
a greenish mineral called olivine. There can also be another pyroxene
variety low in calcium (e.g. hypersthene, pigeonite). There is of course
a wide variation even amongst black granites - some are extrusive,
some are high-level intrusive (hypabyssal) and some are plutonic.
All differ slightly in their mineralogical composition as well as in their
texture, structure, and in the composition of their constituent minerals
(this is what makes the science of rocks so fascinating). Then there
are black granites that have formed from other pre-existing, usually mafic
rock types, through the processes of metamorphism. Because metamorphism
always involves an elevation of temperature and usually involves fluids
a fascinating range of textures can be produced, as well as an assortment
of new (prograde) minerals. There can also be reactions that produce
secondary minerals such as chlorite, a host of other amphiboles, as well
as epidote, talc, serpentine, and smectite clays. Some of these
reactions produce strange textures. Then depending on the composition
of the fluids involved in the metamorphism it is possible to get a number
of other minerals introduced (e.g. quartz, alkali feldspar, sulphides).
Because it is quite difficult to distinguish many of these minerals even
for a scientist let alone a quarryman or stone processor, it is very important
for a stone geoscientist (not a geologist) to analyze the stone petrographically
to determine whether or not it contains any minerals which might cause
problems in performance (serviceability) and durability of the stone.
This type of study can also tell a lot about the origin of the rock and
provides information on its potential for development, its quarryability,
and any problems which might be encountered in the future. I hope this
enlightens you a bit on the mineralogy of black granites. Dr. Hans,
Australia
Comments? Complaints?
Compliments? info@findstone.com
The views expressed
in this section are not of FindStone.
|
