Phenomenal

"Phenomenal" Gemstones


"I am a little world, made cunningly of elements, and an angelic sprite." 

John Donne
1572-1631



"Phenomenal" Gemstones are those that display special optical effects. Such effects include:

Chatoyancy: "Catseye" seen in quartzes and tourmalines

Adularescence: The "sheen" seen in moonstones

Aventurescence: Bright internal sparkles as seen in some quartzes and sunstones

Asterism: Four and Six ray stars seen in rubies and garnets

Color Change: The appearance of different hues under changing light conditions as seen in alexandrite and some sapphires

Iridescence: Spectral colors as seen in pearls and labradorite

Play-of-Color: Colorful flashes seen in precious opal

Most of these effects are the result of trace metallic elements in the crystalline matrix or from mineral inclusions residual to the gem's original formation.

This exhibit presents a number of these effects for your enjoyment and consideration.





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