Gemstone Chart |
Natural Star Sapphire A star sapphire is a lovely gem that exhibits a six pointed star because of the intersection of six thin intersecting inclusions. When the gem is lit from above, the inclusions become quite visible and the star shape appears.A powdery grey-blue star sapphire is the centerpiece of a ring from the Art Deco period. Color: Blue, green blue, violet, blue, black, brown, pink. Categories: semi-precious stone Chemical Composition: AL2O3 Crystal Group: Hexagonal Refractive Index: 1.759-1.778 Hardness: 9 Density: 4 Occurrence: Sri Lanka, Burma, India, East Africa, Ankarana-Madagascar, Thailand.
| Natural Turquoise Turquoise is an opaque, blue-to-green mineral that is a hydrous phosphate of copper and aluminium.The gem turquoise owes it's beauty almost entirely to its superb color. It has been used for ornamentation since 3000BC and possibly before. Color: Blue, Greenish Blue Categories: semi-precious stone Chemical Composition: CuAl6(PO4)4(OH)85H2O Crystal Group: Triclinic Refractive Index: 1.62 Hardness: 5.5-6 Density: 2.60- 2.90 Occurrence: Iran, USA, India, Tibet, China, Egypt, Chile, Russia, Australia
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