Jet

Hair ornament
MFA# 53.2295

Description

A dense, black, lignite Coal that can be carved and polished. Jet is found in large deposits near Whitby in England and in the Asturias in northern Spain. Smaller deposits are found in France, Germany, the Czech Republic, Slovakia, Italy, Portugal, Canada, and the USA. Jet was formed from driftwood from pines of the Araucaria genus that were subjected to intense pressure. The soft, brittle material flakes easily and can be worked with saws, drills and engraving tools. Jet has been used for beads, jewelry, cameos, buttons, and small decorative items since Neolithic times. Jet became popular as mourning jewelry during Victorian times. Imitation jet jewelry has been made from black glass (Paris jet), dyed chalcedony, black tourmaline, obsidian, melanite, ebonite, and vulcanite.

Synonyms and Related Terms

Paris jet; Jett (Deut.); git (Ned.)

Physical and Chemical Properties

• Soluble in white spirit, acetone and other solvents
• Fracture = conchoidal
• Luster = vitreous to greasy
• Streak = brown
• Burns with greenish flame, copious smoke and bituminous smell
• Most become magnetic when rubbed or warmed
• Generates electrical charge when rubbed with wool
• Pleochroism = none
• Fluorescence = inert

Mohs Hardness	2.0 - 3.0
Density	1.15-1.3 g/ml
Refractive index	1.640 - 1.680

Resources and Citations

• Gem Identification Lab Manual, Gemological Institute of America, 2016.
• A. Franco Mata, "Jet" The Dictionary of Art, Grove's Dictionaries Inc., New York, 1996.
• Ralph Mayer, A Dictionary of Art Terms and Techniques, Harper and Row Publishers, New York, 1969 (also 1945 printing)
• Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997
• The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998
• Jack Odgen, Jewellery of the Ancient World, Rizzoli International Publications Inc., New York City, 1982
• A.Lucas, J.R.Harris, Ancient Egyptian Materials and Industries, Edward Arnold Publishers Ltd., London, 4th edition, 1962
• Tom Rowland, Noel Riley, A-Z Guide to Cleaning, Conserving and Repairing Antiques, Constable and Co., Ltd., London, 1981
• George Savage, Art and Antique Restorer's Handbook, Rockliff Publishing Corp, London, 1954
• Art and Architecture Thesaurus Online, https://www.getty.edu/research/tools/vocabulary/aat/, J. Paul Getty Trust, Los Angeles, 2000
• Wikipedia: Jet (gemstone) Accessed Jan 2023