Comments for Mysterious color changing cameo

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perhaps fluorite
by: Anna

Intriguing, I'll definitely look into that possibility some more. In short, my dad studies rocks so I know a little bit. The colors represented are similar to that of the cubed varieties I've seen. It is very clear though - there aren't any bands or inclusions of any kind. If fluorite does color change, that would be a perfect fit! Will probably end up taking it to a gemologist to have it looked at. Thanks so much for your help and I apologize in my delay if response!!

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Fluorite and Blue John
by: Anonymous

Anna
uhmm ....it wouldn't be alexandrite, in short supply, is too hard for carving. With this degree of color change in the purple/blue/green range - I'm wondering if this photochromism phenomenon could account for the mineral fluorite.

"BLUE JOHN" is one of the most famous of the older-known localities of fluorite is Castleton in Derbyshire, England where purple-blue fluorite was extracted from several caves - under the name of "Derbyshire Blue John".

The blue John is now scarce and only a few hundred kilograms are mined each year for ornamental and lapidary use. Recently discovered deposits in China have produced fluorite with coloring and banding similar to the classic Blue John stone. In fluorite the visible light emitted is most commonly blue, but red, purple, yellow, green and white also occur.

Research Fluorite - Anna - Fluorite has traditionally been used for carving decorative objects rather than as a gemstone for jewelry and it's relative softness on the Mohs Scale of Hardness makes it particularly suitable for carving cameos and intaglios.

Warm Wishes
Yvonne Hammouda-Eyre

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GemStone Carving - Amethyst
by: Anonymous

My thought was that it was amethyst as well. I figured out that the color change happens when under different light. I don't know if amethyst is able to change color like that. It's that lavender color in natural light, but under the lamp (when the blinds aren't open or it is night) it looks like a pale blue green. I wish I could add a picture or two of the other color to show you! I didn't even notice the other gold detail - very interesting, indeed! Will search some more - I'm stumped though! Surely it isn't something like alexandrite...I don't know how far back chemically altered glass goes or if it can even do that...

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Cameo Carving Could be Amethyst Material
by: Yvonne

Hi Anna
that sounds like an unusual piece. And what a lovely gift! The carving looks well done too, and quite detailed. It could have been carved as a representation of someone alive at the time. Or in loving memory.

Two of the rosebuds on the surround look like GREEN gold. I can see the rose colored gold at the top of the pendant. The jeweler was certainly trying to impress with these innovative techniques. There is information on different colored gold that was used in antique jewelry. HERE...

The material looks like amethyst. Does the stone change color when you hold it in different directions under light?

Warm Regards
Yvonne

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