Black Spinel
Spinel var. Black Spinel (Magnesium Aluminum Oxide) · Semi-Precious Gemstone / Collector Mineral
Crystal System
Cubic (Isometric); typically forms octahedrons, dodecahedrons, or in massive granules; often found as rounded water-worn pebbles in alluvial deposits
Mineral Group
Oxides (Spinel group)
Chemical Formula
MgAl2O4 with trace amounts of iron (Fe) or chromium (Cr) giving it the black color
Formation Process
Metamorphic or Igneous; forms under high temperature in contact metamorphic environments such as marbles, and as an accessory mineral in mafic igneous rocks
About This Crystal
Jet black, opaque stones with a high-luster vitreous finish. In this jewelry piece, they are round-brilliant or facet-cut, showing a smooth, mirror-like surface reflections typical of high-quality spinel
Physical Characteristics
Color: Opaque black; Streak: White; Luster: Vitreous; Cleavage: Indistinct; Fracture: Conchoidal to uneven; Specific Gravity: 3.58–3.61; Fluorescence: Typically inert
Optical Properties
Refractive Index: 1.712–1.762; Singly refractive (Isotropic); no pleochroism due to cubic structure; high dispersion but masked by opacity
Hardness & Durability
Origin Region
Thailand, Sri Lanka, Myanmar (Burma), Vietnam; typically found in contact metamorphic limestones and alluvial deposits
Hardness & Durability
Mohs Hardness: 8.0; Excellent toughness; highly stable and extremely durable for daily wear in rings
Care & Maintenance
Safe to clean with warm soapy water, ultrasonic cleaners, and steam cleaners. Store separately from softer stones to avoid scratching others
Rarity & Value
Relatively affordable compared to black diamond; value is determined by the quality of the cut and 'jetness' of the black; treatments are very rare
Special Characteristics
Known for its high metallic-like vitreous luster; often used as a natural alternative to black diamond or black tourmaline due to its superior hardness
Lore & History
Historically often confused with black tourmaline or jet; traditionally believed to be a protective stone that repels negativity and grounds the wearer’s energy; associated with the Root Chakra