Garnet
Almandine Garnet · Collector Mineral / Semi-Precious Gemstone
Crystal System
Cubic (Isometric); typically occurs in dodecahedral or trapezohedral habits, often found as rounded crystals or massive granular form
Mineral Group
Silicates (Nesosilicates)
Chemical Formula
Fe3Al2(SiO4)3 with traces of Mg and Mn
Formation Process
Metamorphic; typically forms under high pressure and temperature conditions during regional metamorphism of argillaceous sediments
About This Crystal
The specimen shows a deep reddish-brown to dark brown color with a granular, crystalline texture. It displays a vitreous to resinous luster on fractured surfaces and varies from translucent in thin sections to nearly opaque in massive form.
Physical Characteristics
Color: Deep red to brownish-black; Streak: White; Cleavage: None; Fracture: Subconchoidal to uneven; Specific Gravity: 4.1-4.3; Fluorescence: Usually inert
Optical Properties
Refractive Index: 1.77-1.83; Isotropic (single refraction); No pleochroism due to cubic symmetry; High dispersion
Hardness & Durability
Origin Region
New York (Adirondacks), USA; India; Sri Lanka; Madagascar; commonly found in metamorphic schist belts
Hardness & Durability
Mohs Hardness: 7.0-7.5; Toughness: Fair to Good; very stable against heat and chemical erosion
Care & Maintenance
Wash with warm soapy water; safe for ultrasonic cleaning if no significant inclusions are present; avoid sudden temperature shifts
Rarity & Value
Very common; value is primarily determined by clarity and size of individual crystals rather than industrial massive specimens
Special Characteristics
High iron content makes it slightly paramagnetic; some specimens may contain needle-like rutile inclusions producing asterism
Lore & History
Used since the Bronze Age as gemstones and abrasives; historically known as 'Carbuncles'; traditionally associated with the Root Chakra and vitality/grounding