I bought these beautiful earrings and pendant at an auction. Only describtion was: 21 carat gold, black and white stones.

Black stones RI 1.434.
Under microscope the white stones look colorless. Maybe these are fluorite as well, or what do you think?

Are the stones worthless?

Thanks for your input :blush:


I have never seen antozonite in jewelry. Could be. Have you shined a flashlight through the stone? are they opaque? What are the facet junctions like in the black stones? Sharp? Rounded? Chipped?

Can you post more photos?

Thanks for your reply :blush:
The black stones are opaque. And the facets a little rounded, -but you might consider the facets sharp. I wouldn’t be able to tell the difference.
The picture is taken outside in the sun.

Thank you for the larger photo. The white stones appear to be round brilliant cut. As to exactly what type of stone could be zircon, sapphire or maybe diamond. 21K gold - very expensive gold wire. See if you know a jeweler with a gem tester pen. That should shed some light on these stones. I hope this helps.

Thanks for your reply :blush:
I have had the jewelery at a jeweler as one of the black stones was loose. They didn’t know which stones it was either, but said that people in the East like the color of 21 carat gold and are equally happy with whether the stones are real.
Today I have sent the jewelery to GRS in Paris and then we will see which stones are involved.

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It could be a black sapphire.?

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It is obsidian - a vulcanic glass.
I must learn more, so that I don’t send items like this to be tested.

Can you sell glass (even natural like these) as stones?

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Correct me if i am wrong, but Obsidian is considered a gemstone, even though it is (natural) glass. Therefore these earrings being sold as gemstone earrings is fine.


Obsidian is considered a rock because it contains multiple minerals. It is mostly Quartz and has different compositions depending upon the type of Obsidian. Transparent Obsidian is the rarest. Opaque Black Obsidian is more common, Mohogany Obsidian has red tones mixed with black, Snowflake Obsidian has white Pumice scattered throughout, Sheen Obsidian has a metallic reflectivity. It sounds like you have Black Obsidian, which has no other visible inclusions. Some rocks are also considered to be Gemstones because they are used to make jewelry. So, it is proper to describe Obsidian as a Gemstone as well as a Volcanic Glass. Lapis Lazuli is another Gemstone that is considered to be a rock because it is comprised of several minerals, but it is quite valuable.

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