Tumbled Garnet (Almandine)
Almandine Garnet (Iron Aluminum Silicate) · Semi-Precious Gemstone
Crystal System
Cubic (Isometric); typically forms as dodecahedrons or trapezohedrons, though this specimen is tumbled/polished.
Mineral Group
Silicates (Nesosilicates) - Garnet Group
Chemical Formula
Fe3Al2(SiO4)3
Formation Process
Metamorphic; typically forms under high pressure and temperature during the regional metamorphism of clay-rich sedimentary rocks (pelites).
About This Crystal
A deep reddish-brown to burgundy tumbled stone. Transparent to translucent with a vitreous to resinous luster. It exhibits a smooth, rounded surface with internal fractures and cloudy inclusions characteristic of natural garnet.
Physical Characteristics
Color: Dark red to brownish-red; Streak: White; Cleavage: None; Fracture: Conchoidal to uneven; Specific Gravity: 3.9–4.3; Tenacity: Brittle; Fluorescence: Generally inert.
Optical Properties
Singly refractive; Refractive Index: 1.77–1.83; Absence of pleochroism due to isometric system; Low dispersion; Some specimens may show asterism (4-rayed star) if rutile needles are present.
Hardness & Durability
Origin Region
India, Sri Lanka, Madagascar, Brazil, and the United States (notably Idaho and New York). Found commonly in metamorphic schists and gneisses.
Hardness & Durability
Mohs Hardness: 6.5–7.5; Good toughness due to lack of cleavage; Stable and resistant to most chemicals and fading from light.
Care & Maintenance
Safe to clean with warm soapy water and a soft brush. Avoid extreme temperature shocks (very hot water to cold). Ultrasonic cleaners are usually safe unless there are heavy internal fractures.
Rarity & Value
Very common mineral; value is low for tumbled specimens ($1-$10). High-quality transparent faceted gems are more valuable. Generally untreated, but occasionally fracture-filled.
Special Characteristics
High iron content gives it a higher specific gravity than many other stones of similar look. It may show a weak magnetic pull if using a powerful Neodymium magnet.
Lore & History
Historically used in 'carbuncle' jewelry and as an abrasive. Known as the 'Stone of Health' in lore, traditionally associated with the Root Chakra, vitality, and protection during travel.