Andesine

Andesine is a red feldspar gemstone, sometimes with greenish hints and a slight labradorescent effect. Andesine is a relatively new gem on the market. It first appeared in 2003, though its exact origins were never fully disclosed. There are those who believe that a limited deposit of natural red Andesine from an alluvial source in Congo is the origin of this material. Although this is possible, it has yet to be proven. Aside from a possible natural stock from the Congo, the material on the market today is produced in China by artificially enhancing Labradorite through diffusion treatment with copper.
Chemical Formula (Na,Ca)Al1-2Si3-2O8
Color Red, Green, Yellow, Orange, Pink, Multicolored
Hardness 6Â -Â 6.5
Crystal System Triclinic
Refractive Index 1.560Â -Â 1.568
SG 2.69Â -Â 2.70
Transparency Transparent to translucent
Double Refraction .008
Luster Vitreous
Cleavage 2,1 - basal ; 2,1 - prismatic ; 3,1 - pinacoidal.
Mineral Class Plagioclase feldspar (Also see the minerals Andesine and Labradorite))