Manganese

manganese

hausmannite

ramsdellite

tephroite

Images

Manganese Mn is an element that occurs rarely in the native state.

Specific gravity: 7.01 calculated
Hardness: 6½
Streak: Dark grey
Colour: Steel-grey
Melting point: 1250^oC
Environments

Placer deposits

Manganese has not been approved as a mineral species by the IMA.
It tarnishes on exposure to air and, when heated, oxidises to hausmannite (ChC).
The most stable oxidation state is Mn²⁺, which is a pale pink color in aqueous solutions. Also important is Mn⁴⁺, brown/black, which is found in ramsdellite, and Mn⁷⁺ found in the purple permanganate anion (Mn⁷⁺O₄)^1–. The Mn⁶⁺ oxidation state is green (ChC).
The abundance in the Earth's crust is 0.1% by weight, 360 parts per million by moles (ChC).


Localities

The first recorded locality was in unnamed placers, at Aldan, Sakha Republic, Russia. Manganese occurred as angular grains up to 0.8mm, in platinum group mineral-gold placers derived from serpentinised ultramafic rocks (olivine - orthoclase picrite) in a matrix of tephroite, spessartine, chromium-rich hausmannite and an unnamed manganese carbide, and associated with tephroite, spessartine, orthoclase, olivine and gold (AM88.933, Mindat).

Manganese-bearing minerals include:

Sulphides - the sulphide anion is S^2-

alabandite
hauerite

Sulphosalts - sulphide minerals with the general formula AmBnXp, where A represents a metal , B usually represents semi-metal and X is sulphur or rarely selenium and/or tellurium

benavidesite
clerite
luboržákite
ramdohrite
uchucchacuaite

Oxides - the oxide anion is O^2-

Hydroxides - the hydroxide anion is (OH)^-

asbolane
groutite
lithiophorite
pyrochroite
tetrawickmanite
wickmanite

Carbonates - the carbonate anion is (CO₃)^2-

kutnohorite
rhodochrosite

Monoborates - with a single boron anion (BO₃)^3- or B(O,OH)₄

fredrikssonite
gaudefroyite
jimboite

Diborates - with double boron triangles and/or tetrahedra

sussexite
wiserite

Sulphates - the sulphate anion is (SO₄)^2-

saccoite
shigaite
apjohnite

Tellurates - salts of telluric acid H₆Te⁶⁺O₆

xocolatlite

Tellurites - the tellurite anion is (Te⁴⁺O₃)^2-

kinichilite
spiroffite

Sulphites - the sulphite anion is (SO₃)^2-

mikenewite

Phosphates - the phosphate anion is (P⁵⁺O₄)^3-

Arsenates - the arsenate anion is (As⁵⁺O₄)^3-

Hydrogen Arsenates - the hydrogen arsenate anion is (As⁵⁺O₃OH)^2-
fluckite

Vanadates - the vanadate anion is (V⁵⁺O₄)^3-

ansermetite
brackebuschite
fianelite
medvedevite
palenzonaite
pyrobelonite

Antimonates - the antimonate anion is (Sb⁵⁺O₃)^-

katoptrite
långbanite
manganostibite

Arsenites - the arsenite anion is (As³⁺O₃)^3-

dixenite
magnussonite

Nesosilicates - insular (Si⁴⁺O₄)^4- groups

Sorosilicates - (Si⁴⁺₂O₇)^6- groups

Cyclosilicates - (Si⁴⁺_nO_3n)^2n-

ikranite
labuntsovite-Mn
princivalleite
roeblingite
selsurtite
sergevanite
steenstrupine-(Ce)
tienshanite
tisinalite

Inosilicates - Single Chain - (Si⁴⁺_nO_3n)^2n-

Inosilicates - Double Chain - (Si⁴⁺_4nO_11n)^6n-

Phyllosilicates - (Si⁴⁺₂O₅)^2- groups

Tectosilicate - [Al³⁺_xSi⁴⁺O_yO_(2x+2y)]^x−

helvine
verplanckite

Unclassified silicates

demagistrisite

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