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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
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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