Stone Fruit - Marble or Alabaster?

I'm not sure this is the appropriate forum for this, but I didn't see another one that quite fit.

I have a grouping of stone fruit, looks like olives, apricots, and a mango. It's polished and heavy. From the striations in the stone, I'm thinking it's marble but I'm not sure. I've had alabaster fruit before, and it was not shiny and seemed "softer".

Can you tell from the pictures what stone these are?

Thanks so much,
Janice

 

Hi Janice,
It looks like dyed alabaster to me. Where the wires go in put a drop of white vinegar and look closely with a magnifier. If you see bubbles it is marble. Alabaster is calcium sulfate no fizz. Marble is calcium carbonate it will fizz.
greg

 

Great tip, Greg! I tried the vinegar hack (twice, just to be sure), and it fizzes! Marble it is. Thank you very, very much!

 

@gregsglass
Hi greg, what is onyx? Will it fizz?

From ascot's photos, I was thinking dyed onyx.

 

Hi,
I do not think onyx fizzes or my old rings would have been eaten away. Just a guess.
greg

 

I vote onyx. These usually are.

 

Onyx is a kind of quartz, similar to chalcedony, and does not fizz; or so I've been told.

 

There's true onyx, which is Silicon Dioxide and there's calcite, which is the stuff often sold as onyx. Calcite is Calcium carbonate, which reacts with acid. Marble also contains calcites, but it's far more expensive than the calcite "onyx". Greg's ring will be true onyx, these almost certainly dyed calcite "onyx".

 

They may also be clear urethane dipped for a hard shiny finish.

 

Hi,
I only mentioned my rings since I used to wear a black onyx ring. My hands were always in vinegar, paint remover and other acid chemicals with out gloves. Never had a mark to my gold and onyx signet ring. My silver one was "eaten" to death but not the onyx.
greg

 

....which would explain the "fizz."

 

I vote onyx just because onyx is the most commonly-used mineral for this kind of novelty/decorative item. The striations also look just like those often found in onyx. And yes whatever it is, it has been dyed.

 

onyx

 

They look like Mexican travertine. All sorts of things are carved out of it, and it's routinely dyed.

 

That's what I thought.

 

Looking to learn more about these minerals, I found a discussion which sheds some light but I'd still like more official, generally-accepted definitions.

http://andy321.proboards.com/thread/60394/travertine-onyx

My own observation makes me refer to the stuff used for walls and floors that is usually opaque, as travertine. I call the stuff used for smallish novelty items, that's translucent and solid (no pores) = onyx. But chemically they are the same I guess.

 

Nope. Onyx is Silicon Dioxide, SiO2. http://www.mindat.org/min-2999.html

Marbles, including travertine, are an assortment of carbonate salts of calcium, CaCO3 with Calcium magnesium carbonate, sometimes, CaMg(CO3)2.

So totally different. Calcite is often called onyx, but it isn't. It's calcium carbonate.

Alabaster is CaCO4, calcium sulphate. it's a salt of sulphuric acid and has four O atoms. Sulphites are CO3 and only have three oxygen atoms. (As an aside, a sulphide is any metal/sulphur combo) .

If I think long enough, I might even remember the chemical equations, but it's a few decades since I did this stuff!

 

Y'all are killing me , so smart. Never took chemistry as I was a (o tempora, o mores!) Latin major.

 

Hi OBB,
Thank you, thank you. Your chemistry is almost as good as your Botany.
greg

 

Bear's formula for onyx reminded me of Silly Putty but when I looked it up Silly Putty is composed of 65% dimethyl siloxane (hydroxy-terminated polymers with boric acid), 17% silica (crystalline quartz), 9% Thixatrol ST (castor oil derivative), 4% polydimethylsiloxane, 1% decamethyl cyclopentasiloxane, 1% glycerine, and 1% titanium dioxide, in case you want to mix some in your kitchen. And onyx doesn't bounce like silly putty.