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Jet  (variety of Lignite, Coal)
Current inventory:  0 gems
 

Chemistry:  C,H,O •2H₂O  [Hydrated Hydro Carbon]

Discovered in Prehistory;   IMA status: Not Valid (a mineraloid).
The English word/name "jet" is derived from the French word for the same material: jaiet.

Classification

Mineral Classification:

Organic Compounds (Mineraloids)

Strunz 8th Ed. ID:

9

Nickel-Strunz 10th Ed. ID:

10

10

Related to:

Variety of Lignite, Coal

Crystal Data

Crystallography:

Amorphous

Crystal Habit:

None

Twinning:

None

Physical Properties

Cleavage:

None

Fracture:

Irregular/Uneven

Tenacity:

Brittle

Hardness (Mohs):

~2.0 - 2.5

Density:

~2.0 (g/cm³)

Luminescence:

None

Radioactivity:

Not Radioactive

Optical Properties

Color:

Black, very dark Brown

Transparency:

Opaque

Luster:

Vitreous, Resinous

Refractive Index:

None, Opaque

Birefringence:

None, Opaque

Dispersion:

None

Pleochroism:

None

Occurances

Geological Setting:

A product of high pressure decomposition of wood from millions of years ago.

Common Impurities:

Fe, S

Type Locality:

None, Prehistoric; possibly Tagabau Garzweiler near Grevenbroich, Germany

Year Discovered:

Prehistoric

View mineral photos:

Jet Mineral Photos and Locations

More Information

Mindat.org  (Jet)
Mindat.org  (Lignite)
Mindat.org  (Coal)

Jet is a hard, "gem" variety of Lignite. Lignite is a variety of Coal that retains the structure of the original wood. Lignite is also called brown coal. Jet is more dense and highly compressed than Lignite. The adjective jet-black, to describe the deepest black color, is better-known perhaps than the substance from which the descriptive phrase derives.

Jet is not considered a true mineral, but rather a mineraloid due to its organic origin, being derived from decaying wood under extreme pressure. Jet is either black or very dark brown, and may contain Pyrite inclusions. Jet is easily polished and is used in jewelry. Jet jewelry has been found dating from about 10,000 BC in parts of contemporary Germany. The oldest jet jewelry was found in Asturias, Spain, dating from 17,000 BC. Jet as a gem material was highly popular during the reign of Queen Victoria. Jet was popular for mourning jewelry in the 19th century because of its sombre color and modest appearance, and it has been traditionally fashioned into rosaries for monks. In the United States, long necklaces of jet beads were very popular during the 1920s, or Roaring Twenties.

Jet is found at many localities worldwide including Latrobe Valley, Australia; and Tagabau Garzweiler near Grevenbroich, Germany; Asturias, Spain; and the Herrin coal beds of the Illinois Basin, USA.
 

  
Jet gems for sale:

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