Cristinite - A trade name for an artificial glass gem material produced in Australia.
Crystal Glass - A glass containing additives to increase dispersion and RI.
Lead Glass - A crystal glass containing up to 40% wt. lead oxide.
Goldstone - A glass containing flecks of copper.
Libyan Desert Glass - A natural yellow glass found in the western desert of Egypt.
Apache Tears - Small rounded pebbles of black Obsidian found in American Southwest.
Mahogany Obsidian - A variety of Obsidian with black and red banding.
Rainbow Obsidian - Obsidian with multicolored iridescence.
Sheen Obsidian - A variety of obsidian exhibiting a golden sheen effect.
Snowflake Obsidian - A variety of obsidian containing white "snowflake" crystal patterns of the mineral cristobalite.
Paste - Glass without additives, also known as common glass.
|Photos of natural/un-cut material from mindat.org|
|Can be coated with metal foils - Gemmological Tables, Ulrich Henn and Claudio C. Milisenda, 2004, p 2|
|Physical Properties of Glass|
|Mohs Hardness||4 to 6Gemmological Tables (2004) , More from other references|
|Specific Gravity||2.39 to 4.00Gemmological Tables (2004) , More from other references|
|Fracture||ConchoidalManagement Team (2012) ,|
|Optical Properties of Glass|
|Refractive Index||1.48 to 1.70Gemmological Tables (2004) , More from other references|
|Optical Character||IsotropicGemmological Tables (2004) ,|
|Colour (General)||Various, play of colourGemmological Tables (2004) , More from other references|
|Causes of Colour||Yellowish green, Fe2+ in octahedral coordination. Brown Fe3+ in octahedral coordinationPragmatic Spectroscopy For Gemologists (2011) ,|
|Transparency||Transparent,Translucent,OpaqueGemmological Tables (2004) , More from other references|
|Lustre||VitreousManagement Team (2012) ,|
|Fluorescence & other light emissions|
|Fluorescence (Short Wave UV)||Strong chalky fluorescence commonBlue Chart Gem Identification (2010) ,|
|Crystallography of Glass|
|Crystal System||AmorphousBlue Chart Gem Identification (2010) , More from other references|
|Inclusions in Glass|
|Gas bubbles, swirl marks, partly tabby extinction - Gemmological Tables, Ulrich Henn and Claudio C. Milisenda, 2004, p 2|
|Mineral information:||Glass information at mindat.org|