Peridot (Olivine)
Olivine var. Peridot (Magnesium Iron Silicate) · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Orthorhombic; typically occurs as rounded grains or massive granular aggregates (as seen in peridotite xenoliths)
Mineral Group
Silicates (Nesosilicate)
Chemical Formula
(Mg, Fe)2SiO4 (Magnesium iron silicate with trace amounts of nickel and chromium)
Formation Process
Igneous formation; specifically formed deep within the Earth's mantle and brought to the surface by basaltic magmas as xenoliths
About This Crystal
An olive-green to yellowish-green granular specimen. The texture is sugary (saccharoidal) and translucent, consisting of many small interlocked crystals with a vitreous luster.
Physical Characteristics
Color: Olive-green; Streak: Colorless/White; Cleavage: Poor; Fracture: Conchoidal to uneven; Specific Gravity: 3.27-3.37; Fluorescence: Generally inert.
Optical Properties
Refractive Index: 1.654–1.690; Birefringence: 0.035–0.038; Pleochroism: Weak (yellow-green to green); Doubly refractive.
Hardness & Durability
Origin Region
Notable sources include San Carlos (Arizona, USA), Pakistan, Myanmar (Burma), and Zabargad Island (Egypt)
Hardness & Durability
Mohs Hardness: 6.5 to 7.0; Toughness: Fair to good; Sensitivity: Sensitive to rapid temperature changes and strong acids.
Care & Maintenance
Clean with warm soapy water and a soft brush; avoid ultrasonic or steam cleaners. Avoid contact with sulfuric or hydrochloric acid.
Rarity & Value
Common as a mineral; gem-quality is more uncommon. Value is determined by color (pure green is most valuable), size, and absence of dark inclusions (chromite).
Special Characteristics
Idiochromatic (colored by its own chemical composition); frequently contains 'lily pad' inclusions (discoid liquid-and-gas stress fractures) in faceted gems.
Lore & History
Historically known as the 'Gem of the Sun' by ancient Egyptians; it was often confused with Emerald. Traditionally associated with the Heart Chakra and believed to promote abundance and protection.