Bismuth

bismuth

bismuthinite

pegmatite

hydrothermal

Images

Formula: Bi native element
Specific gravity: 9.7 - 9.8
Hardness: 2 to 2½
Streak: Lead grey
Colour: Silver white
Solubility: Slightly soluble in hydrochloric acid, readily soluble in sulphuric and nitric acid
Common impurities: Fe,Te,As,S,Sb
Environments:

Pegmatites
Metamorphic environments
Hydrothermal environments

Bismuth occurs in pegmatites and as an unaltered primary mineral in hypothermal (high temperature), tin ore veins. It is widespread, although not in large amounts, in contact metamorphic formations, where it generally occurs in chalcopyrite aggregates, and more rarely in arsenopyrite (Ramdohr p379-380).
In pegmatites associated minerals include chalcopyrite, pyrrhotite, arsenopyrite, pyrite, bismuthinite, molybdenite, sphalerite, galena, wolframite and cassiterite, as well as cubanite and cobaltite.
In vein deposits associated minerals include skutterudite, safflorite, löllingite, bismuthinite, silver, nickeline and breithauptite (Ramdohr p379-380).

Localities

The Needle Hill Mine, Needle Hill, Sha Tin District, New Territories, Hong Kong, China, is a tungsten mine, abandoned in 1967. The principal ore is wolframite, and the principal gangue mineral is quartz. Molybdenum also occurs. The mineralisation consists of a series of parallel fissure veins that cut through granite. Wolframite and quartz are the main minerals, but galena, sphalerite, pyrite, molybdenite and fluorite have also been found here (Geological Society of Hong Kong Newsletter 9.3.29-40). The quartz-wolframite veins are of high-temperature hydrothermal formation, and grade into wolframite-bearing pegmatites.
Wolframite is almost always associated with molybdenite. Other associated minerals found occasionally include pyrite, chalcopyrite, arsenopyrite, sphalerite, bismuth, fluorite, topaz and cassiterite (Hong Kong Minerals (1991). Peng, C J. Hong Kong Urban Council)

At the Emmons pegmatite, Greenwood, Oxford county, Maine, USA, bismuth has been found as 1-2 mm grains, often coated with beyerite and associated with bismuthinite. The Emmons pegmatite is an example of a highly evolved boron-lithium-cesium-tantalum enriched pegmatite (R&M 94.6.505).

Bismuth-bearing minerals include:

Alloys
maldonite

Sulphides
bismuthinite
tetradymite
thalhammerite

Sulphide/Selenides
laitakarite
nevskite

Selenides
guanajuatite
kawazulite
paraguanajuatite

Tellurides
hedleyite
michenerite
tellurobismuthite
montbrayite
volynskite

Tellurobismuthides
moncheite

Bismuthides
froodite
insizwaite
kotulskite
polarite
sobolevskite

Sulphosalts
aikinite
benjaminite
cosalite
cupropavonite
emplectite
friedrichite
galenobismutite
gladite
gustavite
heyrovskýite
hodrušite
jonassonite
krupkaite
lillianite
lindströmite
matildite
miharaite
mozgovaite
nuffieldite
ourayite
pavonite
wittichenite
wittite

Oxides
bismite
bismutotantalite
oxybismutomicrolite
sillénite
sphaerobismoite
uranosphaerite

Halogenides
bismoclite

Carbonates
beyerite
bismutite

Tellurites
yecoraite

Phosphates
mrázekite
petitjeanite

Arsenates
asselbornite
atelestite
mixite
preisingerite
rooseveltite
tetrarooseveltite
walpurgite

Vanadates
dreyerite
namibite
pucherite
schumacherite

Molybdates
koechlinite

Nesosilicates
eulytine

Phyllosilicated
bismutoferrite

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