Jordisite

jordisite

ilsemannite

molybdenite

uraninite

Images

Formula: MoS2
Sulphide of molybdenum, paramorph of molybdenite
Crystal System: Seems amorphous
Specific gravity: Not determined
Hardness: 1 to 2
Streak: Grey, blue-grey
Colour: Black, blue-grey
Environments

Hydrothermal environments

Jordisite occurs as veinlets and coatings of probable medium- to low- temperature hydrothermal origin. Associated minerals include ilsemannite, molybdenite, uraninite, coffinite, kerogen ( a mixture of organic chemical compounds that make up a large portion of the organic matter in sedimentary rocks), cinnabar, pyrite, fluorite, apatite, stilbite, calcite and quartz (HOM).

Localities

At the copper mines of the Carrizal Alto district, Huasco Province, Atacama Region, Chile, the black, apparently amorphous phase which clearly veins molybdenite-3R is a molybdenum disulphide that may be jordisite. The occurrence of this mineraloid at Carrizal Alto differs from those previously described in that ilsemannite is apparently absent, and jordisite itself has the appearance of a secondary product. Wulfenite and tungstenoan wulfenite, the oxidation products of molybdenite characteristic of this district have not been observed in specimens from the Carrizal Alto mine dumps (AM 56.1832-1834).

At the Zunyi Ni-Mo-PGE-Au ore field, Bozhou District, Zunyi, Guizhou, China, jordisite occurs in metalliferous Cambrian (538.8 to 485.4 million years ago) black shales.
Because powder diffraction-like SAED (selected area electron diffraction) patterns were obtained, jordisite is not strictly speaking amorphous (AM 86.852-861).

The type locality is the Himmelsfürst Mine, Brand-Erbisdorf, Mittelsachsen, Saxony, Germany.

Kiggins, Oak Grove Fork, Clackamas County, Oregon, USA. A study of material from this locality indicates ilsemannite is derived from a black colloidal molybdenum sulphide, namely jordisite. Furthermore, unlike the most common occurrence of molybdenite, jordisite appears to be a low-temperature product, as indicated by its association with cinnabar and zeolites. This, together with the relative rarity of jordisite, may explain the scarcity of ilsemannite in most molybdenite deposits. In those few cases where ilsemannite has been reported as associated with or derived from molybdenite, it is likely that some jordisite was also present (AM 36.609-614).

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