Almandine Garnet in Matrix
Garnet group, Almandine species · Mineral Specimen / Semi-Precious Gemstone
Crystal System
Cubic (Isometric); commonly occurs as dodecahedral or trapezohedral crystals, though here seen as fractured grains in a schist/rock matrix.
Mineral Group
Silicates (Nesosilicates)
Chemical Formula
Fe3Al2(SiO4)3 (Iron Aluminum Silicate)
Formation Process
Metamorphic: Forms under high pressure and temperature during the regional metamorphism of clay-rich sedimentary rocks (pelites).
About This Crystal
Deep reddish-brown to dark red crystals embedded in a dark, potentially micaceous or basaltic matrix. The garnet shows a vitreous to resinous luster where fractured, exhibiting characteristic transparency in small fragments pinned against the opaque host rock.
Physical Characteristics
Color: Deep red to brownish-red; Streak: White; Cleavage: None; Fracture: Subconchoidal to uneven; Specific Gravity: 4.1-4.3; Fluorescence: Usually none; Tenacity: Brittle.
Optical Properties
Refractive Index: 1.77-1.83 (Singly refractive); Birefringence: None; Pleochroism: None; Dispersion: 0.027; Luster: Vitreous.
Hardness & Durability
Origin Region
Globally distributed; notable sources include India, Sri Lanka, USA (New York, Idaho), and Austria. Often found in regional metamorphic rocks like mica schists.
Hardness & Durability
Mohs Hardness: 7.0 - 7.5; Toughness: Fair to Good; Stability: Very stable, resistant to most chemicals and light fading.
Care & Maintenance
Clean with warm soapy water and a soft brush. Avoid extreme temperature shocks. Generally safe for ultrasonic cleaning if no significant fractures are present.
Rarity & Value
Common; Value is determined by size, clarity, and color of the crystals. Matrix specimens are valued as educational or collector items rather than high jewelry.
Special Characteristics
May show slight magnetism due to high iron content. Some specimens can exhibit asterism (star effect) if rutilated, though not visible in this specimen.
Lore & History
Historically used as an abrasive and in signet rings. Legend suggests garnets light up the night and protect travelers. Modernly associated with the Root Chakra and believed to promote grounding and physical strength.