Isn't marble more than quartzite?

I wonder how all those kitchens (both private and commercial) and all those bathrooms made it into this century with the same marble that was put into them 100 years ago.

I don't know if it's an across the board statement, but the quartzites we've looked at our more expensive than the marble we also liked.

and yes, I've wondered the same about how all the kitchens with marble have "survived" just fine, but in seeing pictures of etching and just knowing myself, I know I'm not willing to take the risk. I just don't want to be the crazy person watching over everyone in the kitchen.

[LOL]

Well, sorry I don't have an answer for you!

You have excellent diagnostic and observational skills there, Reno, good work! The rock is not scratching glass if you can rub off the mark. Quartzite is super obvious in how it scratches glass. It really bites into the glass and you can feel it in your hand, hear it, and it leaves a clear, permanent gouge in the glass.

You can try pushing harder (be careful not to break the glass in your hand though). You can also try putting a couple drops of vinegar on it and watch if it fizzes. If at first it doesn't fizz, do it again and look through a magnifying glass.

"I wonder how all those kitchens (both private and commercial) and all those bathrooms made it into this century with the same marble that was put into them 100 years ago."

They didn't have a polished finish.

bear with me - I don't know what I'm doing but I tried to upload a picture of the slab I have on hold. It looks like it's a link to the picture.

I know the real answer is "no" but is there any way to get an IDEA from a picture if something is marble or quartzite? anything about the appearrance that suggests one more than the other?

Does the sample have a sharp edge or is it rounded? While quartzite will scratch glass, it needs a reasonable edge to do it. For an extreme example, our quartzite counters have a bull nose and don't scratch anything. If the sample is ball like, perhaps lack of an edge is the problem.

If the sample has a sharp edge or corner to scratch with and isn't scratching, then it's not quartzite.

The appearance of quartzite and calcium-based stones (marble, dolomite, etc.) can be pretty similar so I don't think that will help. Acid or scratching are the way to tell.

Since the sample is walnut size, perhaps you could even submerge it in white vinegar in a small glass or bowl and see if after a while some of it has dissolved into the vinegar.

It really looks the same as Super White, sorry to say.

Be careful of the glass test with super white. Our super white, which is mostly marble, has veins of a much harder stone running through it (the clearish/milky/opalescent white parts). Those veins neither etch nor scratch--my counter has zillions of tiny little scratches, but wherever they cross one of the harder veins, the scratch is interrupted until it gets to the softer marble part again.

Also, be aware it may not fizz right away with vinegar. If I put vinegar on a chunk from the slab that made my bathroom marble counters (calacatta gold), it will fizz and etch immediately. If I put the same type of vinegar on my super white kitchen counters, it will not fizz, and it doesn't leave an etch mark at all if it's wiped off within a minute or two. I don't know why there's such a difference in etching speed, but it does make my kitchen counters much easier to live with.

To test it, I'd recommend letting the vinegar or lemon juice sit for half an hour and then check for a mark. I suspect you'll see one because I think it's the same as super white, which Karin MT says is dolomitic marble.

Windy Lindy is right, some Super White does have a bit of quartz in it and it can fool the scratch test. It still lacks the "bite" of real quartzite when you scratch glass, but unless you have both on hand to compare, that's not a particularly helpful measure.

Super White etches more slowly than most marble because it's dolomitic marble rather than regular ol' marble made from calcite. The mineral dolomite (which is made from magnesium carbonate as well as calcium carbonate) is less reactive to acid.

As for submerging the sample in vinegar, I'm not sure how you'd tell if it dissolved or not. The geologist's diagnostic for dolomite is to either scratch up the surface of the rock to make a little powder, and then put acid on the powdered part, or to put acid on the rock and then watch through a magnifying glass to see if there are bubbles weakly fizzing up in the acid.

And yes, I agree with Cloud Swift that you need to do the diagnostics to tell quartzite from marble. It's really hard to tell just by looking, unfortunately.

Good luck!