I don't know if anyone else will find this useful, but I did

some controlled experiments to see what (if anything)

damaged some stone samples, after not being able to find

anything resembling consensus on such questions as "will

windex damage granite," or "do you have to dry off marble

right away when it gets wet"....

I tested samples of silestone (Olive), granite (Tropical

Green), and Onyx.

I tested acid (5 M acetic acid) and base (baking soda

paste, didn't have ammonia and was afraid to use NaOH from

my lab) on the Onyx: base was fine and acid left a slight

cloud/discoloration after a few minutes of exposure. Water,

no matter how long I left it, didn't do anything. My

understanding is that onyx is a more delicate version of

marble, so the implication is that bases and water are

also fine for marble but NTBCAK[kitchen]A

Silestone: I tested acid, base, heat, direct flame,

acetone, alcohol, windex (weak base), bleach, comet,

various foods, inks, and scratching (variety of things).

And I put it through the

dishwasher. It was totally unscathed, except for:

direct flame, after about four minutes got a small scorch

mark, and my diamond ring, which scratched it as promised

("only diamond will scratch quartz").

Granite: First, on the unpolished side, I tested

bleach, sharpie, ketchup, open flame (5 min), grape

juice, windex, oil, acetone, alcohol, strong acid (HCl),

weak acid (5 M acetic), tea, baking soda, water. All but

the sharpie, ketchup, oil, and HCl wiped off. Then I

put it through the dishwasher. It came out with a slightly

pitted surface *only* where the HCl had been. Some of

the sharpie was also still there; the rest was perfect.

Then I tested the polished side, I re-tested the HCl and

the sharpie. They both wiped/rinsed off after a few minutes

with no seeming ill effects, though I did not leave

them longer than maybe 10 minutes.

I conclude that it should be A-OK to windex any of the

materials, and that we should avoid strong HCl on anything

in the kitchen (!) except perhaps Silestone. Bleach should

also be fine - again NTBCAKA. :)

In general this makes sense with my chemistry knowledge;

whatever susceptible parts of the stones there are, are

likely calcium salts which will be hurt by acids but

not bases. After seeing what the acetic acid did to the

onyx, I wouldn't recommend onyx as a counter since lots

of common foods/drinks are on the weak-acid spectrum.

--Leah