Black Spinel
Spinel (variety: Black Spinel) · Semi-Precious Gemstone
Crystal System
Cubic (Isometric); typically forms as octahedral crystals or dodecahedrons; featured here as faceted round beads
Mineral Group
Oxides (Spinel Group)
Chemical Formula
MgAl2O4 with trace Fe3+ (iron) and Cr3+ (chromium) causing black coloration
Formation Process
Metamorphic; typically forms during regional or contact metamorphism of limestone and dolomites, or as an accessory mineral in basic igneous rocks
About This Crystal
Jet-black, opaque to sub-translucent beads with high vitreous to sub-adamantine luster. The faceted surfaces display sharp reflections and a consistent deep black color across the strand without visible zoning.
Physical Characteristics
Color: Jet black; Streak: White; Cleavage: None/Indistinct; Fracture: Conchoidal; Specific Gravity: 3.58 - 3.61; Tenacity: Brittle; Fluorescence: Generally inert to weak under UV
Optical Properties
Refractive Index: 1.718; Single Refraction (Isotropic); Luster: Vitreous; Opaque body prevents pleochroism and dispersion from being visible
Hardness & Durability
Origin Region
Thailand, Myanmar (Burma), Sri Lanka, and Tanzania; typically found in alluvial deposits or contact metamorphic marbles
Hardness & Durability
Mohs Hardness: 8.0; Toughness: Good; Highly stable and durable for daily jewelry wear due to lack of cleavage and high hardness
Care & Maintenance
Clean with warm soapy water and a soft brush; safe for ultrasonic and steam cleaning unless fracture-filled; store separately to avoid scratching softer stones
Rarity & Value
Relatively common compared to Red Spinel; priced by carat weight and cut quality; more affordable and durable alternative to Black Diamond or Black Sapphire
Special Characteristics
Known for its exceptionally high vitreous luster and intense black saturation; lacks the 'peppered' look of black tourmaline or the gray undertones of hematite
Lore & History
Historically often confused with black tourmaline or ruby (in its red form); in lore, it is considered a stone of protection and grounding, associated with the Root Chakra and rejuvenation of energy