Black Diamond
Carbon var. Diamond (Carbonado-type or Treated) · Precious Gemstone
Crystal System
Cubic (Isometric); typically found as massive or polycrystalline aggregates in black varieties.
Mineral Group
Native Elements
Chemical Formula
C (Pure Carbon, with inclusions of graphite, magnetite, or hematite in natural stones)
Formation Process
Natural black diamonds (Carbonados) are thought to form in supernovae or high-pressure metamorphic environments; commercial black diamonds are often natural white diamonds that have undergone irradiation or high-heat treatment.
About This Crystal
Opaque black gemstone with a high adamantine luster. These stones exhibit a metallic to sub-metallic shine on the surface and are comprised of many tiny crystals fused together, giving them a dense, light-absorbing appearance.
Physical Characteristics
Color: Opaque black; Streak: White; Cleavage: None (due to polycrystalline structure) or octahedral in single crystals; Fracture: Conchoidal to splintery; Specific Gravity: 3.51; Fluorescence: Often none, but may show inert to moderate green or blue.
Optical Properties
Refractive Index: 2.417 (Opaque); Birefringence: None (Singly Refractive); Luster: Adamantine; Dispersion: N/A (opaque, no fire visible).
Hardness & Durability
Origin Region
Central African Republic, Brazil (for natural carbonados); laboratory-processed worldwide for irradiated black diamonds.
Hardness & Durability
Mohs Hardness: 10; Toughness: Excellent (in polycrystalline form) to Good (in single crystal); extremely durable for daily jewelry wear.
Care & Maintenance
Clean with warm soapy water or ultrasonic cleaner. While highly durable, they should be stored separately to avoid scratching other gems. Avoid extreme thermal shock if the stone is heavily included.
Rarity & Value
Natural 'Fancy Black' diamonds are rare; most commercial jewelry uses treated black diamonds which are relatively affordable, typically ranging from $100 to $1,000 per carat depending on size and polish.
Special Characteristics
Polycrystalline structure in natural carbonados makes them tougher and harder to cut than standard clear diamonds; treated versions rely on surface-reaching fractures to absorb dyes or radiation effects.
Lore & History
Historically avoided in some cultures as 'bad luck' due to their dark color, they are now symbols of inner strength and authority. In modern practices, they are associated with the Root Chakra and protection.