Image: James St. John (CC BY 2.0)
trigonaluncommonOxides
Sapphire
Al2O3
The image displays a faceted, deep blue sapphire gemstone, showcasing its characteristic vitreous luster and transparent quality, likely cut for use in jewelry.
Sapphire Physical Properties
Mohs Hardness
9Crystal System
trigonalLuster
vitreousStreak Color
whiteCleavage
None (parting often present)Fracture
conchoidalSpecific Gravity
3.95Colors
blue, pink, yellow, green, purple, orange, colorless, blackTransparency
transparentType Locality
Sri Lanka, Madagascar, Australia, Thailand, Myanmar, Kashmir (India), Montana (USA)Mineral Group
OxidesUses
jewelry, abrasives, watch bearings, scientific instrumentsAssociated Minerals
feldspar, mica, garnet, spinel, kyaniteRarity
uncommonGeological Context
Sapphire, a variety of corundum, forms in various igneous and metamorphic rocks, including basalts, syenites, gneisses, and schists, often under high-temperature and high-pressure conditions. It is also found in alluvial deposits due to its hardness and resistance to weathering.
