chemical, technical characteristics of other in general
|| other, bluestone, slate, onyx, engineered
stone, manufacture stone, basalt, pebbles, flagstone, lava
Q 2304: In your response to a question that read "Does anyone have
any particular do/don'ts when dealing with un-gauged Indian Slate?
Dave, March 4." You responded "don't". Would you expand on that short
answer please? I have also considered 12" gauged multicolored slate for
kitchen, entry, hallway, but don't care to make an expensive mistake.
What is your opinion of china white / gold quartzite? Thanks-much!!
Leslie, July 26,
|Q 2244: Does anyone have
empirical information (or even an opinion) regarding the comparative
heat resistance of granite and "manufactured
stone" (such as zodiaq and Silestone)? Because I would
wanted a very light colored countertop, I was leaning towards manufactured
stone. I read, however, something that suggested that manufactured
stone shouldn't be used as a regular "landing pad" for stuff coming
out of the oven. Marianne, July 16.
Dear Marianne: Whoever told you that was right. The approximately
6% of resin in engineered stone (which is the bonding agent of the
quartz chips) could be damage by the
heat of a pot.
Now, about this thing that light colored "granite" is usually bad
as far as maintenance is concerned> True geological granite is either
white, or light gray, or pinkish, and its porosity is quite controllable
with a good quality sealer! are those color light enough for you?
Check the "Bianco Sardo" granite (a.k.a. "Luna Pearl"). It's a great
stone! Maurizio, USA
|Q 2178: I would be grateful
for advice on what method I should adopt to get a marble
effect on slate, I am aware that the slate has to be painted
black to begin with, but after that, what product/method and tools
should I use to obtain the best result. Barry, July 8,
Dear Barry: I must know something that I don't know! In fact, unlike
you, I'm not aware that slate has to be painted black. I actually
never heard of such a silly thing! And what about getting "the marble
effect"? I really wish I knew what you're talking about!! Ciao and
good luck, Maurizio, USA
Can you give me some information about zodiaq, its pro and
cons? Maria, June 30, .
Dear Maria: "zodiaq" is a so-called engineered
stone. It's manmade by mixing quartz crystals (94%,
I believe to remember) with epoxy resin (the reminder 6%). If you
like the way it looks, there are not many cons I can think of. Ciao
and good luck, Maurizio, USA
|A 1952: We
purchased some onyx
wine glasses and the sales rep said they were unsafe to drink
from. Can you advise? Vicky, May 22,
Dear Vicki: The safety
aspect really depends on what you are drinking, how much, and
with whom. I presume that you are referring to onyx marble rather
than onyx which is a semi-precious variety of agate used for the manufactures
of cameos, rings, cuff-links (showing my age), and intaglios. The
name onyx has been used historically for a number of rock types including
alabaster, marble and chalcedony. Assuming that yours are onyx marble
the main danger is to your glasses rather than to you because of the
reaction between marble and anything acidic. Wine is acidic and will
etch the marble (partly dissolve it). In doing so it will necessarily
leach into the wine any substances that might be contained within
the marble. Simply avoid drinking from these glasses unless it is
pH neutral water. (Dr. Hans), Australia
Vicky: Wow, two salespeople
in a row that are right!! That's a first all right! Wine is acidic
(acetic acid) and will corrode all calcite-based stones, Onyx among
them and first of all! Do NOT pour wine in those things of beauty!
It won't do your health any harm, but it will alter the taste of the
wine while slowly destroying the stone. Maurizio, USA
|A 1913: Hi!
Where can I find info and facts about basalt
rocks for a science project? Thanks, Angel, May 16,
Dear Angel: Be an angel
and get off your backside and look up some books that contain information
about the most widespread and common rock on this earth (and the Moon).
There would literally be many millions of pages written about basalt!
|A 1708: I saw a picture
of the industrial & Commercial bank of China in Shanghai Very
curious to know what effect can Onyx
create to the bank ? What finishes to use on Onyx to make the
wall lively? Patricia, April 14.
Dear Patricia: What do you mean with "What finish to use on Onyx
to make the walls lively?" Onyx, like any other stone that can be
polished, is polished by abrasion and friction, not by putting some
sort of finish onto it. Of course, like any other Calcite-based stone
it's very sensitive to pH active chemicals, including rain, pollutants,
etc., therefore it is certainly NOT a stone that you want to consider
Talking about China, I am personally consulting with the company in
charge of maintenance of the new head quarters of the Bank of China
in Beijing. They finished the building over two years ago, but it
still not occupied. They cladded all the outside walls with polished
Italian Travertine. A stone like that, much as Onyx, can't be used
outdoors, so I went to the trouble of formulating a special sealer
-- both penetrating and topical -- to help minimize and delay the
damages that the exposure to the weather will produce eventually.
In over two years, they never reached a decision, and, by now, the
whole thing is already in need of a serious restoration procedure.
Considering the size of the walls (close to 200,000 square feet. No
it's not a typo!), the technical difficulties attached to the project
and -- most importantly -- the glacied pace to which the Chinese Bureaucracy
moves, I can only envision one big mess! But, hey, I'm still on! Ciao,
|A 1575: My name is Michelle
& I am an interior decoration student in Sydney, Australia.
I have been asked to research pebbles.
I need to find out - history, properties, UV light effect, slip resistance,
effect from oils, effect from acids etc. strength, maintenance, fire
resistance. March 21.
Michelle, LOL there are so many different types of pebbles that you
basically can't get a response. You need to narrow your research down
to specific types of pebbles with specific properties first. Write
back for help when you have narrowed your request down. Steven, USA
|A 1559: IS SANDSTONE
OR FLAGSTONE FOUND IN OKLAHOMA ? ARE THEY THE SAME STONE?
THANKS. GWEN. March 20.
Dear Gwen.. Sandstone is a geologic term describing a particular type
of stone, i.e.. a sedimentary stone composed primarily of sand (quartz)
sized grains. The amount and type of inter grain cementing materials
determines the density and relative hardness of the stone. Flagstone
is a descriptive term referring to stone that is relatively flat on
both surfaces with a uniform thickness that breaks into random shapes.
Any sedimentary stone can be a flagstone if it was deposited in thin,
distinct layers with a definite break in the deposition between the
layers. I have seen both sandstone, and siltstone flagging from OK.,
and limestone is often found as a flagstone type. JVC,
They could be. Yes there is sandstone in Oklahoma. Regards, Steven,
|A 1476: Please tell me
the difference between Slate tile and Quartzite
tile, if any and which would cost more. Thank you. Harold, USA,
The primary difference is mineral composition and physical make up.
The cost is relative to where you are and what is available. In my
part of the country they are pretty equal in cost. Regards, Steven,
|A 1301: What
are the costs/benefits of granite vs.
silestone? I know that granite's beauty is incomparable,
but I am concerned about staining and susceptibility to heat. I have
read that silestone is great, but can be manufactured in sheets no
longer than 10, so there are problems with seams. Donna, USA, Jan
From the perspective you are viewing this both materials could work
for you. The natural stone would need to checked for absorbency. Many
stones don't absorb very much. Susceptibility to heat affects some
of the darker engineered stones so give that vote to natural stone.
Cost wise engineered stone is less expensive to begin with. So you
are left with aesthetics and your willingness to investigate natural
stone. On this forum, we would like for you to personally check the
absorbency of the stone by conducting Maurizio's now infamous lemon
juice test. Scroll through previous answers to find it. Best regards,
Dear Donna: It's impossible to answer your question with black and
white statements. There are too many grey areas. Engineered stones
(and Silestone among them) are only relatively less expensive than
"granite" (approx. $5 per square foot), therefore price is hardly
a motivation to choose a material over the other one. The advantage
with engineered stones is that are more predictable, as far as maintenance
is concerned. In fact, "granite" is much more unpredicatable, due
to the fact that the vast majority of the stones traded as granite
are not granite by a long shot. What's more important, is the fact
that the vast majority of the stone fabrication facilities' operators
are just as "intelligent" about "granite" as you are. In fact, they've
got their stone education from a whole army of salesmen and the importer/distributor's
invoices. Most of them don't even know that what they sell as granite
is not, in fact, granite. Hence, all the confusion and the different
hearsay about "granite" countertop. Some end-users are delighted,
some others, at the other end of the spectrum, are just about ready-to-kill-the-who-sold-granite-to-them.
What's my advice? I'm too much in love with natural stone to encourage
you to buy something else, but I do understand your concerns (by the
way, "granite" is way more heat resistance than engineered stone).
I devised a little test ("the lemon just test") that anybody can run,
and that you can find somewhere else in this site, which helps a lot
at narrowing down the selection of natural stone. When shopping around,
do NOT listen to anybody: just run the test and rely on it. It's honest
and unbiased. Ciao, good luck, and have fun in the process, Maurizio,
Your observations are correct. Granite is a natural stone and has
its own character. Like all natural stones, it has its own beauty
but with it comes some of the defects (not all materials made by God
are perfect). Sometimes we try and cure most of the defects to enable
the stone to perform equal to manmade stones. Manmade stones are mere
agglomerates of stone chips/powder in resins/binders and then cast
into sheets. You can compare it with pre-cast concrete where stone
aggregates mixed with cement is cast. Silestone will give you an impervious
surface but will not have the natural look. It will be like synthetic
leather v/s original leather. Arun, India,
I have a number of clients asking about?? Pyroclastic Lava.
Could you tell me about the product in relation to use in countertops.
I remember it as glass-like porous material from Geology classes. Thanks,
USA, Oct 5.
"Pyroclastic lava" makes no sense. There are products of lava flows
or pyroclastic flows. Lava flow products examples are basalt, andezite,
rhyolite. Pyroclastic flow products examples are tuff, welded tuff or
volcanic Breccia. Some porous basalts are named lava stones. There are
not suitable for countertops without sealing. They are not polishable,
They are mainly of black to dark grey colors. Daniel, Slovakia,
A 1109: I am a research student looking for
relevant information on serpentine.
Ty, USA, Sept 24,
is usually dark green, veined, often brecciated, metamorphic rock which
was formed from upper mantle peridotite rocks during collision of lithospheric
plates. It is created from serpentinite and small amount of calcite, magnetite,
chromite and pyroxene. The hardness of serpentinite is similar to marbles,
but it is chemically more stable. Daniel, Slovakia
A 1087: I am trying to find a product
called bluestone. I don't know if
it is granite, marble or limestone. Please advise. Angela, USA, Sept.
R6: Bluestone is
not marble granite or limestone - it describes a type of stone that is
not easily cut to a specified dimension. Flagstones can be described
as bluestone as they are used as irregular shape slabs often in the shape
that they are extracted from the ground. The opposite of bluestone
is "free stone" or "dimension stone", such as sandstone and marble that
can be freely cut to size. Regards, Jim, Australia,
R5: It is a stone similar in properties
to slate. Domestic varieties come from Pennsylvania, New York and North
Carolina. Steven, USA.
R4: Bluestone is a name for sandstone that is quarried in NJ and
PA. You should be able to find it at most stone suppliers. Fred, USA.
R3: Unfortunately for you, bluestone is a loose term in the
stone trade meaning different things in different countries. Even
in the same country, bluestone can vary dramatically in composition and
appearance. For example, in Australia, bluestone is a basalt in
Victoria and used mainly for paving; a volcanogenic greywacke (sandstone)
in Queensland; and an impure, fine sandstone that has been metamorphosed
to a low grade, in South Australia. The South Australian bluestone is
similar to the Italian Cardoso stone. So what you have to do is find out
what the specifiers of your American stone mean by bluestone. Hans,
is a sedimentary/ metamorphic stone. In the United States, it is quarried
in south central New York and northern Pennsylvania. It has many of the
qualities of slate like a natural cleft, and have color variations too
that are beautiful. You may know it as "Flagstone". It is used for patios,
sidewalks, and for veneer on basements and chimneys. Burzin, India.
It is not granite, it is not marble, its not limestone either. Amazingly,
it is ... Well, Bluestone! Large quantities can be found in Pennsylvania.
Ciao. Maurizio, USA,
1019: As we are considering to import and distribute slate
for roof covering, I am missing lab tests regarding content
of Calcium carbonate (lime) which has a negative effect on the quality
of slate. Also, some types of slate are difficult to cut/form. Could you
please direct me how to find guidelines about the various quality characteristics
for slate? Bjorn, USA. June 21 reply
R1: A good starting
point is the established ASTM test methods as follows:
ASTM C120 - Flexure testing of slate
ASTM C121 Water Absorption of slate
ASTM C217 - Weather Resistance of slate
Jim Man, Australia Contact