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Formula: Bi
Native element, arsenic group
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 Johanngeorgenstadt, Erzgebirgskreis, Saxony, Germany, native bismuth was among the most important products
of the mines. Bismuth generally occurred as fine disseminations in
quartz and chert-rich veins,
and as impregnations in the country rock. More rarely it was found as massive granular to leafy aggregates, and as
intergrowths with cobalt and nickel
ores. The feathery to herring-bone habit so well-known at Schneeberg was rare but formed specimens of exceptional
beauty; feathery crystal aggregates to 6 cm were found with pitchblende,
reddish brown chert or
dolomite. Bismuth specimens from the Gewerken Hoffnung mine are
particularly rich and fine. Small bismuth crystals, an extreme rarity, were found in the Gabe Gottes and
Gottes Segen mines
(MinRec 55.5.590).
Bismuth from Johanngeorgenstadt -
Image
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
driekopite
froodite
maldonite
polarite
Sulphides
bismuthinite
demicheleite-(Br)
demicheleite-(Cl)
demicheleite-(I)
ikunolite
joséite-A
laitakarite
nevskite
tetradymite
thalhammerite
vymazalováite
zipserite
Selenides
guanajuatite
kawazulite
padmaite
paraguanajuatite
Tellurides
hedleyite
kanatzidisite
maslovite
michenerite
tellurobismuthite
pilsenite
volynskite
Sulphosalts
aikinite
aramayoite
aschamalmite
benjaminite
berryite
buckhornite
cosalite
cuprobismutite
cupromakovickyite
cupropavonite
eldragónite
emplectite
friedrichite
galenobismutite
gladite
gustavite
heyrovskýite
hodrušite
holubite
jonassonite
krupkaite
kupčíkite
lillianite
lindströmite
makovickyite
malyshevite
matildite
miharaite
mozgovaite
nuffieldite
ourayite
padĕraite
pavonite
pekoite
petrovicite
terrywallaceite
treasurite
vikingite
watkinsonite
wittichenite
wittite
Bismuthides
insizwaite
sobolevskite
Tellurobismuthides
kotulskite
moncheite
montbrayite
Oxides
bismite
bismutocolumbite
bismutotantalite
fluornatromicrolite
mambertiite
oxybismutomicrolite
sardignaite
sillénite
sphaerobismoite
uranosphaerite
Chlorides
bismoclite
Carbonates
beyerite
bismutite
kettnerite
Sulphates
aiolosite
atlasovite
elasmochloite
markhininite
Tellurates
montanite
Selenites
favreauite
Tellurites
bodieite
yecoraite
Phosphates
brendelite
mrázekite
petitjeanite
phosphowalpurgite
waylandite
Arsenates
asselbornite
atelestite
juanitaite
mixite
paganoite
preisingerite
rooseveltite
tetrarooseveltite
walpurgite
Vanadates
dreyerite
namibite
pucherite
schumacherite
Molybdates
koechlinite
Tungstates
russellite
Nesosilicates
eulytine
Phyllosilicates
bismutoferrite
Alloys - an alloy is a substance that combines more than one metal or mixes a metal with other non-metallic
elements
Sulphides - the sulphide anion is S2-
Selenides - the selenide anion is Se2-
Tellurides - the telluride anion is Te2-
Sulphosalt - AmBnXp: where A is a metal , B usually a semi-metal and X
is sulphur, selenium or tellurium
Bismuthides - the bismuthide anion is Bi3-
Tellurobismuthides - bismuthides where tellurium replaces some bismuth
Oxides - the oxide anion is O2-
Chlorides - the chloride anion is Cl-
Carbonates - the carbonate anion is (CO3)2-
Sulphates - the sulphate anion is (SO4)2-
Tellurates - salts of telluric acid H6Te6+O6
Selenites - the selenite anion is (Se4+O3)2-
Tellurites - the tellurite anion is (Te4+O3)2-
Phosphates - the phosphate anion is (P5+O4)3-
Arsenates - the arsenate anion is (As5+O4)3-
Vanadates - the vanadate anion is (V5+O4)3-
Molybdates - the molybdate anion is (Mo6+O4)2-
Tungstates - the tungstate anion is (WO6+O4)2-
Nesosilicates - insular (Si4+O4)4- groups
Phyllosilicates - (Si4+2O5)2- groups
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