Image: <a rel="nofollow" class="external text" href="https://www.flickr.com/people/47445767@N05">James St. John</a> (CC BY 2.0)
trigonalcommonOxides
Sapphire
Al₂O₃
A transparent, faceted blue sapphire gemstone, exhibiting a rich, deep blue color and excellent clarity.
Sapphire Physical Properties
Mohs Hardness
9Crystal System
trigonalLuster
vitreousStreak Color
whiteCleavage
none (parting common)Fracture
conchoidal to unevenSpecific Gravity
4Colors
blue, pink, yellow, green, purple, orange, colorlessTransparency
transparent to translucentType Locality
Sri Lanka, Madagascar, Australia, Thailand, Montana (USA), KashmirMineral Group
OxidesUses
jewelry, industrial abrasives, watch bearings, scientific instrumentsAssociated Minerals
feldspar, mica, garnet, spinelRarity
commonGeological Context
Sapphire forms in aluminum-rich igneous rocks (such as basalts and syenites) and metamorphic rocks (like schists and gneisses), frequently found in placer deposits due to its high hardness and resistance to weathering.
