SUNSTONE


All facts and figures taken from the GIA

SUNSTONE

Sunstone’s phenomenal varieties show a distinct and lively glitter called aventurescence. Sunstone is a member of the feldspar group. Both the orthoclase and the plagioclase feldspar species boast a sunstone variety. Other feldspar group gems include moonstone, non-phenomenal orthoclase, phenomenal and non-phenomenal labradorite, and amazonite.


MINERAL: Feldspar
CHEMICAL COMPOSITION: Orthoclase – KAlSi3O8
Oligoclase and labradorite – solid solution between NaAlSi3O8 and CaAl2Si2O8
COLOR: Yellow, green, red, red-brown, colorless
REFRACTIVE INDEX: Orthoclase sunstone – 1.518 to 1.526
Oligoclase sunstone – 1.537 to 1.547
Labradorite sunstone – 1.559 to 1.568
BIREFRINGENCE: Orthoclase – 0.005 to 0.008
Oligoclase and labradorite – 0.007 to 0.010
SPECIFIC GRAVITY: Orthoclase – 2.58
Oligoclase – 2.65
Labradorite – 2.70
MOHS HARDNESS: 6.0 – 7.2


Alexandrite is a birthstone for June, along with pearl and moonstone. Alexandrite is also the gem for the 55th wedding anniversary.

FOUND WHERE

Precious_Gemstone_Where_Found_Sunstone