Garnet (specifically Almandine or Pyrope)
Almandine-Pyrope series (Fe3Al2Si3O12 to Mg3Al2Si3O12) · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Cubic (Isometric); typically occurs as dodecahedral or trapezohedral crystals, or massive/water-worn pebbles
Mineral Group
Silicates; specifically Nesosilicates within the Garnet Group
Chemical Formula
Fe3Al2(SiO4)3 (Almandine) with potential Magnesium substitutions
Formation Process
Primarily Metamorphic (formed in schists and gneisses) or Igneous (formed in pegmatites or volcanic rocks)
About This Crystal
A dark, deep red to nearly black tumbled stone. It exhibits a vitreous to sub-vitreous luster with a smooth, polished surface showing some internal fractures and characteristic dark inclusions.
Physical Characteristics
Color: Deep burgandy/dark red; Streak: White; Cleavage: None; Fracture: Conchoidal to uneven; Specific Gravity: 3.5 - 4.3; Fluorescence: Generally inert
Optical Properties
Singly refractive (Isotropic); Refractive Index: 1.72 - 1.83; Pleochroism: None; Dispersion: 0.024-0.027
Hardness & Durability
Origin Region
India, Sri Lanka, Brazil, Madagascar, and USA (notably Idaho and New York)
Hardness & Durability
Mohs Hardness: 6.5 - 7.5; Toughness: Fair to Good; Highly stable and suitable for daily jewelry wear
Care & Maintenance
Clean with warm soapy water and a soft brush; avoid sudden temperature changes and harsh acids; ultrasonic cleaners are generally safe if no liquid inclusions exist
Rarity & Value
Common; Value depends on clarity and size. Massive or opaque tumbled stones are inexpensive, while faceted gems of high clarity command higher prices.
Special Characteristics
May exhibit asterism (4 or 6-rayed stars) if rutile needles are present; often contains 'silk' or crystal inclusions typical of metamorphic origin
Lore & History
Historically used as 'Carbuncles' in ancient jewelry; symbolized protection for travelers. In traditional lore, it is associated with the Root Chakra and believed to promote vitality and grounding.