Black Garnet (Andradite or Melanite)
Andradite var. Melanite · Mineral Specimen / Semi-Precious Gemstone
Crystal System
Cubic (Isometric) - Rhombic dodecahedron or Trapezohedron
Mineral Group
Silicates (Nesosilicate) - Garnet Group
Chemical Formula
Ca3Fe2(SiO4)3 (with Ti substitutions)
Formation Process
Metamorphic or Igneous (found in skarns, contact zones, or alkaline igneous rocks like nepheline syenites)
About This Crystal
Deep black to dark brown opaque crystals with a high adamantine to sub-metallic luster. Commonly found as a cluster of well-defined dodecahedral crystals sharing a host rock matrix.
Physical Characteristics
Color: Jet black to dark brownish-black. Streak: White or gray. Fracture: Conchoidal to uneven. Specific Gravity: 3.7 to 4.1. Non-fluorescent.
Optical Properties
Refractive Index: 1.88-1.91 (Isotropic). High dispersion. Opaque in hand specimen, but may show deep brown translucency on thin edges.
Hardness & Durability
Origin Region
Mali, Kazakhstan, Italy (Elba), Mexico, and the USA (California)
Hardness & Durability
Mohs Hardness: 6.5 to 7.0. Brittle toughness but relatively durable for jewelry.
Care & Maintenance
Clean with warm soapy water and a soft brush. Avoid ultrasonic cleaners and sudden temperature changes.
Rarity & Value
Uncommon. Value is driven by crystal size, luster, and sharpness of the crystal faces. Often affordable for collectors.
Special Characteristics
Titanium-rich variety known for its deep black color and brilliant reflection (adamantine luster).
Lore & History
Historically used in mourning jewelry; traditionally associated with grounding, protection, and the root chakra.