Jet (lignite)
mineraloid and minor gemstone
Jet is a geological material considered to be a minor gemstone. It is originally a wood product called lignite, squeezed and heated by geological processes. The older definition of mineral did not apply to organic material. Therefore, jet was not called a mineral, but instead a mineraloid. However, this view is changing, as so many crystalline materials have organic origin.[1]
![](http://up.wiki.x.io/wikipedia/commons/thumb/c/c6/Schwarzer_Trauerschmuck2.jpg/220px-Schwarzer_Trauerschmuck2.jpg)
![](http://up.wiki.x.io/wikipedia/commons/thumb/1/15/Small_sample_of_jet.jpg/220px-Small_sample_of_jet.jpg)
The English noun "jet" comes from the French word for the same material: jaiet.[2] Jet is either black or dark brown, but may contain pyrite inclusions,[3] which are of brassy colour and metallic lustre. The adjective jet-black, meaning as dark a black as possible, comes from this material.
References
change- ↑ Discussed in part II of: L.B. Railsback Definitions [1] Archived 2013-03-02 at the Wayback Machine and [2] Archived 2012-09-15 at the Wayback Machine
- ↑ Oxford English Dictionary 1989. 2nd ed, Oxford University Press.
- ↑ Pye K. 1985. Electron microscope analysis of zoned dolomite rhombs in the Jet Rock Formation (Lower Toarcian) of the Whitby area, U.K. Geological Magazine, 122, 279-286. doi:10.1017/S0016756800031496