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: 630.79^oC
Boiling point: 1587^oC
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 Wet Swine Gill, Coombe Height, Caldbeck, Allerdale, Cumbria, England, UK, veins of native antimony in association with coatings of yellow bindheimite have been found (AESS).
Antimony from Wet Swine Gill - Image

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.
























The commonest ore of antimony is stibnite

Antimony-bearing minerals include:

Alloys - an alloy is a substance that combines more than one metal or mixes a metal with other non-metallic elements
Arsenides - the arsenide anion is As^3-
Antimonides - the antimonide anion is Sb^3-
Sulphides - the sulphide anion is S^2-
Selenides - the selenide anion is Se^2-
Tellurides - the telluride anion is Te^2-
Sulphosalt - A_mB_nX_p: where A is a metal , B usually a semi-metal and X is sulphur, selenium or tellurium
Oxides - the oxide anion is O^2-
Hydroxides - the hydroxide anion is (OH)^-
Chlorides - the chloride anion is Cl^-
Sulphates - the sulphate anion is (SO₄)^2-
Tantalates - salts of tantalic acid (Ta⁵⁺O₃)^-
Tellurites - the tellurite anion is (Te⁴⁺O₃)^2-
Antimonates - the antimonate anion is (Sb⁵⁺O₃)^-
Antimonites - the antimonite anion is (Sb³⁺O₃)^3-

Back to Minerals