Jet
Organic gem
Also called Whitby jet and Gagate
About it
Hard, black fossil wood that takes a velvety polish and feels warm and light. Whitby, England, made it famous for Victorian mourning jewellery; a hot needle smells of burning coal, unlike glass or plastic.
- Type
- Organic gem
- Group
- Fossil wood (lignite)
- Hardness (Mohs)
- 2.5–4
- Specific gravity
- 1.3–1.35
- Streak
- dark brown
- Lustre
- waxy, resinous
- Colours
- black, dark brown
- Transparency
- opaque
- Cleavage and fracture
- none; conchoidal fracture
Typical values: real specimens vary. For more, see mindat.org.