Sunstone
Plagioclase Feldspar (Oligoclase or Andesine) with Hematite/Goethite inclusions · Semi-Precious Gemstone
Crystal System
Triclinic; typically occurs in massive or granular habits in tumbled stones
Mineral Group
Silicates (Tectosilicates); Feldspar Group
Chemical Formula
(Na,Ca)(Al,Si)4O8 with Fe2O3 (Hematite) or Cu (Copper) inclusions
Formation Process
Igneous/Magmatic; forms in pegmatites and lava flows where inclusions like hematite or copper platelets exsolve and orient during cooling
About This Crystal
The specimen is a tumbled, translucent to opaque stone with a warm peach-to-orange body color. It exhibits a vitreous to pearly luster and characteristic 'schiller' effect or aventurescence caused by light reflecting off internal mineral platelets.
Physical Characteristics
Color: Oranges, browns, and peaches with metallic glitters; Streak: White; Cleavage: Perfect in two directions at nearly 90 degrees; Fracture: Uneven to conchoidal; Specific Gravity: 2.62–2.67; Fluorescence: Usually inert but sometimes weak red under SW UV
Optical Properties
Refractive Index: 1.537–1.552; Birefringence: 0.007–0.010; Optical Phenomenon: Aventurescence (metallic glitter); Doubly Refractive
Hardness & Durability
Origin Region
Notable sources include Norway (Tvedestrand), India, Madagascar, and the United States (Oregon - though Oregon variety often contains copper inclusions)
Hardness & Durability
Mohs Hardness: 6.0–6.5; Toughness: Poor to fair due to cleavage; Wearability: Suitable for earrings and pendants, requires care in rings
Care & Maintenance
Clean with warm soapy water and a soft brush; avoid ultrasonic cleaners and steam cleaners which can stress cleavage planes; avoid harsh chemicals and sudden temperature changes
Rarity & Value
Common to uncommon; value is driven by the intensity of the schiller effect and transparency. Oregon Sunstone (copper-bearing) is generally more valuable than Indian or Norwegian varieties
Special Characteristics
Aventurescence: A distinct metallic-like glitter caused by tiny, plate-like inclusions of hematite, goethite, or copper that reflect light like tiny mirrors
Lore & History
Historically linked to the sun and used by Vikings for navigation (though often confused with Iceland Spar); in lore, it is believed to bring luck, vitality, and solar energy; associated with the Sacral and Solar Plexus chakras