gemstone
Sapphire
Corundum (Al2O3)
Hardness of 9 on the Mohs scale, typically blue but can be various colors except red (which is ruby), adamantine to vitreous luster, trigonal crystal system, no true cleavage (parting only), specific gravity of 4.0
Identified More gemstone →
Explore Sapphire in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness of 9 on the Mohs scale, typically blue but can be various colors except red (which is ruby), adamantine to vitreous luster, trigonal crystal system, no true cleavage (parting only), specific gravity of 4.0
Formation & geological history
Formed in metamorphic and igneous rocks, particularly in silica-deficient environments like marble, pegmatites, and basaltic rocks, often over millions of years.
Uses & applications
Used primarily in fine jewelry, watch crystals, scientific instruments, and abrasive applications.
Geological facts
Sapphire is the birthstone for September and has historically symbolized royalty, truth, and sincerity. Star sapphires exhibit a phenomenon called asterism.
Field identification & locations
Identified by its exceptional hardness, high specific gravity, and distinct hexagonal crystal habit when rough. Found worldwide, with major deposits in Sri Lanka, Madagascar, Australia, and the US.
More like this
Other gemstone specimens
Gemstone Ring
N/A - Set piece of jewelry, likely Amethyst or Garnet with Diamond or CZ
gemstone
Diamond and Gold Jewelry
Carbon (Diamond) / Au (Gold)
gemstone
Ammolite
Ammolite (Biogenic Aragonite with trace elements; fossils of Placenticeras meeki and Placenticeras intercalare)
mineral
Cubic Zirconia (simulant) or Diamond
ZrO2 (Cubic Zirconia) or C (Diamond)
gemstone
Red Jasper
Silicon Dioxide (SiO2) with Hematite inclusions
sedimentary
Black Opal Ring (Carved Opal)
Hydrated Silicon Dioxide (SiO2·nH2O)
gemstone