Pyroxmangite
Current inventory:  0 gems
 

  
Pyroxmangite is named after its resemblance to PYROXenes and containing MANGanese.

Discovered in 1913;   IMA status: Valid (pre-IMA; Grandfathered)

Chemistry

Chemical Formula:

Mn,Fe²⁺SiO₃

Manganese Iron Silicate

Molecular Weight:

131.20 gm

Composition:

Manganese

33.50 %

Mn

43.25 %

MnO

Iron

8.51 %

Fe

10.95 %

FeO

Silicon

21.41 %

Si

45.79 %

SiO₂

Oxygen

36.58 %

O

100.00 %

100.00 %

= TOTAL OXIDE

Classification

Mineral Classification:

Silicates (Germanates)

Strunz 8th Ed. ID:

8/F.31-20

Nickel-Strunz 10th Ed. ID:

9.DO.05

9 : SILICATES (Germanates)
D : Inosilicates
O : Inosilicates with 7-, 8-, 10-, 12- and 14-periodic chains

Related to:

Pyroxmangite Group. Pyroxferroite - Plumalsite Series. Dimorph of Rhodonite.

Varieties:

None

Synonyms:

None

Crystal Data

Crystallography:

Triclinic - Pinacoidal

Crystal Habit:

Crystals typically tabular, to 10 cm; porphyroblastic, granular.

Twinning:

Lamellar on {010}, simple on {001}, uncommon.

Physical Properties

Cleavage:

{110} Perfect, {110} Perfect

Fracture:

Irregular/Uneven

Tenacity:

Brittle

Moh's Hardness:

5.5 - 6.0

Density:

3.61 - 3.80 (g/cm³)

Luminescence:

None

Radioactivity:

Not Radioactive

Other:

Magnetic after heating.

Optical Properties

Color:

Pink, Rose Pink, Purplish Pink, Red; commonly covered with Brown or Black oxidation products

Transparency:

Translucent to Transparent

Luster:

Vitreous to Pearly

Refractive Index:

1.728 - 1758  Biaxial ( + )

Birefringence:

0.0160 - 0.0180

Dispersion:

Moderate; r > v

Pleochroism:

None

Occurances

Geological Setting:

In regionally metamorphosed manganese ore deposits and manganiferous rocks, perhaps with lower temperature history than rhodonite-bearing rocks.

Common Associations:

Alabandite, Alleghanyite, Hausmannite, Pyrophanite, Rhodochrosite, Rhodonite, Spessartine, Tephroite

Common Impurities:

Al, Fe, Mg, Ca, Na, K, H₂O

Type Locality:

Tunaberg skarns, Tunaberg, Nyköping, Södermanland, Sweden.
"Type material" from Iva, South Carolina, USA, has been redefined as pyroxferroite, as Fe > Mn.

Year Discovered:

1913

View mineral photos:

Pyroxmangite Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Pyroxmangite is a very rare gemstone that is difficult to cut due to its perfect cleavage. The mineral is usually found as small grains that are seldom large enough or clean enough to facet. Pyroxmangite is similar in appearance and properties to Rhodonite and Bustamite.

There are very few locations for gem quality crystals. Nice crystals have been found at Broken Hill, New South Wales, Australia and Minas Gerais, Southeast Region, Brazil.
 

  
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