Antimony

antimony

silver

arsenic

stibnite

Images

Formula: Sb
Native element, metalloid, arsenic group
Forms a series with arsenic
Specific gravity: 6.61 to 6.71
Hardness: 3 to 3½
Streak: Grey
Colour: Tin-white
Antimony has the unusual property that, like water, it expands as it freezes. Four other elements expand when they freeze, namely silicon, bismuth, gallium and germanium (ChC).
Melting point: 630.79oC
Boiling point: 1587oC
Common impurities: As
Environments:

Hydrothermal environments

Abundance is 0.2 parts per million by mass, 0.03 parts per million by moles in the Earth's crust, and 950 parts per billion by mass, 10 parts per trillion by moles in the Solar System (ChC)
Antimony is seldom found in the native state, but it does occur in antimony-silver hydrothermal veins with silver, antimony and arsenic minerals (Webmin, Dana, HOM). Associated minerals include silver, stibnite, stibarsen, sphalerite, pyrite, galena and quartz (HOM, Dana, Mindat).

Localities

At the Driggith mine, Caldbeck Fells, Cumbria, England, UK, minute grains of antimony are associated with inclusions of bournonite in galena (C&S).

Alteration

skinnerite to chalcocite, antimony and sulphur
2Cu3SbS3 → 3Cu2S + 2Sb + 3/2S2
(CM 28.725-738)

Zn-tetrahedrite to chalcocite, antimony, sphalerite and sulphur
Cu10Zn2Sb4S13 → 5Cu2S + 4Sb + 2ZnS + 3S2
(CM 28.725-738)

Zn-tetrahedrite to skinnerite, antimony, sphalerite and sulphur
3Cu10Zn2Sb4S13 → 10Cu3SbS3 + 2Sb + 6ZnS + 3/2S2
(CM 28.725-738)

The diagram below is a Pourbaix diagram for antimony (GSJ). It shows the relationship between antimony Sb and cervantite/clinocervantite Sb2O4.

Pourbaix antimony.jpg






















The commonest ore of antimony is stibnite

Antimony-bearing minerals include:

Alloys
stibarsen
stistaite

Sulphides
cetineite
costibite
kermesite
pääkkönenite
stibnite
ullmannite
willyamite

Antimonides
allargentum
breithauptite
stibiopalladinite
sudburyite

Sulphosalts
berthierite
bournonite
chabournéite
dadsonite
franckeite
freibergite
heteromorphite
skinnerite
sorbyite
tetrahedrite

Oxides
biehlite
cervantite
clinocervantite
rosiaite
senarmontite
valentinite

Hydroxides
mopungite

Halides
nadorite

Antimonates
bindheimite
brizziite
ordoñezite
stibiconite
tripuhyite

Back to Minerals