Jet
Jet (Lignite variety of coal) · Organic Gem
Crystal System
Amorphous
Mineral Group
Organic Mineraloid
Chemical Formula
Carbon-based organic precursor with variable hydrocarbons
Formation Process
Sedimentary fossilization of compressed wood from prehistoric tree species (such as Araucoxylon) under high pressure in marine environments
About This Crystal
Tumbled, polished organic gemstone featuring a solid, deep black body color with a high, glass-like luster and a smooth, rounded surface shape containing minor natural fissures and growth lines typical of fossilized wood
Physical Characteristics
Color is deep jet black; streak is brownish-black; cleavage is absent; fracture is conchoidal to uneven; specific gravity ranges from 1.30 to 1.34; tenacity is brittle yet surprisingly lightweight
Optical Properties
Refractive index is approximately 1.66; isotropic due to amorphous structure; completely opaque with a velvety to sub-metallic luster on highly polished surfaces
Hardness & Durability
Origin Region
Whitby, Yorkshire, England; Spain; United States
Hardness & Durability
Mohs hardness of 2.5 to 4.0; low toughness and easily scratched or damaged by hard objects; sensitive to heat, solvents, and prolonged exposure to strong acids
Care & Maintenance
Clean gently with a soft, damp cloth and mild soap; avoid ultrasonic cleaners, steam, harsh chemicals, alcohol, and prolonged direct sunlight; store separately in a soft pouch
Rarity & Value
Uncommon to rare for top-quality antique-grade material; value depends on uniform color, lack of structural cracks, and historical provenance; highly valued in antique mourning jewelry
Special Characteristics
Very lightweight compared to stone beads of similar size; becomes negatively charged when rubbed (triboelectric effect); burns with a smoky flame and bituminous odor when ignited
Lore & History
Historically used since the Neolithic period and famously carved into mourning jewelry during the Victorian era by royal decree of Queen Victoria; traditionally associated with grounding, protection, and absorbing negative energy in crystal healing lore