Jet Polished Mineral Specimen

JET

HISTORY, NAME, LOCALITIES: Jet has served as a gemstone since prehistory.  Its name comes from jaiet, the French word for the same material.  Collecting localities are found in Austria, Poland, England, Canada, Spain, Russia, and the United States (Maryland, Colorado, Utah, New Mexico).

MINERALOGY, PROPERTIES, OCCURRENCE: Jet, pronounced as it is spelled, is classified as mineraloid and has neither a definite chemical composition nor a crystal structure.  It has a Mohs hardness of 2.0-2.5, no cleavage, a conchoidal fracture, and a very low specific gravity of 1.1-1.3.  It is jet-black in color with occasional dark-brown streaks and has a vitreous luster on freshly broken surfaces.  Jet has an organic origin, consists primarily of carbon, and is a form of lignite coal that originated as ancient trees that grew in fresh-water swamps, then floated down rivers to sink in seas and become buried and compacted in a salt-water environment.  It occurs as lenses in a hard shale known as “jet-rock.”

METAPHYSICAL PROPERTIES, LORE, USES: Jet jewelry was popular during the Roman period when it was thought to deflect the gaze of the “evil eye.”  It again gained great popularity as gemstone in mourning jewelry during the Victorian Era.  Easily carved and polished, jet is used to fashion rosary beads and ornamental objects.  Metaphysical practitioners believe that jet removes negative thoughts and energies, protects against illness and violence, produces calmness and serenity, and reduces feelings of depression.

COLLECTORS’ INFORMATION: Jet is collected for its unusual biological origin and jet-black color.