Peridot
Olivine var. Peridot (Forsterite) · Semi-Precious Gemstone
Crystal System
Orthorhombic; typically found as flattened grains or prismatic crystals
Mineral Group
Silicates (Nesosilicates)
Chemical Formula
(Mg, Fe)2SiO4
Formation Process
Forms deep within the Earth's mantle; brought to the surface by volcanic activity in basaltic rocks or found in pallasite meteorites.
About This Crystal
A vibrant olive-green to lime-green gemstone, often transparent with a vitreous (glassy) luster and oily appearance.
Physical Characteristics
Yellowish-green color; white streak; poor cleavage; conchoidal fracture; specific gravity 3.27-3.48; no fluorescence.
Optical Properties
Refractive index 1.65-1.69; high birefringence (often showing doubling of back facets); weak pleochroism.
Hardness & Durability
Origin Region
Notable sources include San Carlos, Arizona, USA; Pyaung Gaung, Myanmar; and Kohistan, Pakistan.
Hardness & Durability
6.5 - 7 on Mohs scale; fair toughness; sensitive to thermal shock and rapid temperature changes.
Care & Maintenance
Clean with warm, soapy water; avoid ultrasonic cleaners, steam cleaners, and strong acids; store separately to prevent scratching.
Rarity & Value
Common in small sizes; rare in large, eye-clean crystals over 10 carats; generally untreated and reasonably priced.
Special Characteristics
Features Lily Pad inclusions (discoid tension cracks surrounding a chromite crystal) and strong doubling of facets.
Lore & History
Known to the Ancient Egyptians as the Gem of the Sun; traditionally associated with the Heart Chakra and believed to promote abundance.