GLASS

1940s yellow gold and platinum ring set with diamonds and red glass

Species:  Glass
​​Mohs Hardness:  5.5 out of 10
Color:  Glass occurs in all colors, including colorless.
RI:  Usually between 1.470 & 1.700, but can go OTL
Birefringence:  None
SR/DR/AGG:  SR, commonly with ADR
Pleochroism:  None
Spectrum:  Not diagnostic
Fluorescence:  Variable, not diagnostic
SG:  Usually between 2.30 and 4.50

Glass Facts

Costume butterfly brooch set with glass

Glass occurs in all colors, and is commonly used as an imitation for many gems.

​Glass will have gas bubbles and/or flow marks when magnified.

Goldstone is a variety of glass with a glittery appearance caused by a phenomena known as aventurescence.
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Glass Gallery

All photos courtesy of Scott Papper, GIA GG, AJP, CMA (NAJA)