Black Diamond
Diamond (Carbon var. Carbonado) · Precious Gemstone
Crystal System
Cubic (Isometric); typically found as polycrystalline aggregates or rounded masses
Mineral Group
Native Elements
Chemical Formula
C (Carbon) with graphite or amorphous carbon inclusions
Formation Process
Igneous/Metamorphic; formed at extreme pressure and temperature in the Earth's mantle, potentially influenced by meteoric impact or extraterrestrial origin in the case of carbonado
About This Crystal
Opaque black stones with a sub-metallic to adamantine luster. These are faceted rounds in a pavé setting, exhibiting a dense, dark appearance due to numerous dark inclusions (graphite, hematite, or magnetite).
Physical Characteristics
Color: Black; Streak: White (on specialized plates); Cleavage: None (due to polycrystalline nature) to Perfect (monocrystalline); Fracture: Conchoidal; Specific Gravity: 3.51-3.53; Fluorescence: Usually inert but can be variable.
Optical Properties
Refractive Index: 2.417 (singly refractive); Birefringence: None; Opaque (no pleochroism or dispersion visible); Luster is adamantine.
Hardness & Durability
Origin Region
Primarily Central African Republic and Brazil, found in alluvial sedimentary deposits
Hardness & Durability
Mohs Hardness: 10; Toughness: Exceptional (higher than white diamonds due to polycrystalline structure); Stability: High, but sensitive to extreme heat during repair.
Care & Maintenance
Clean with warm soapy water and a soft brush; ultrasonic cleaners are generally safe but use caution if the stone has surface-reaching fractures/treatments. Store separately to avoid scratching other jewelry.
Rarity & Value
Rarity: Uncommon; Value factors: Carat weight and surface polish quality. Note: Many commercial black diamonds are treated via irradiation or high-pressure high-temperature (HPHT) to achieve uniform black color.
Special Characteristics
Polycrystalline structure; unlike white diamonds which are a single crystal, most natural black diamonds are clumps of millions of tiny crystals stuck together.
Lore & History
Historically considered cursed in some ancient Indian cultures due to their dark color, but now symbolize inner strength and authority. Modern lore associates them with the Root Chakra and protection against negative energy.