Helvine - Occurrence, Properties, and Distribution

Helvine is a yellowish mineral, containing iron, manganese, glucina, silica, and small amounts of sulfur. It was named after the Latin word helvus, which means yellow.

Properties of Helvine

The following are the key properties of Helvine:

• Cell Data
  • Space Group: P43n
  • a = 8.24-8.29
  • Z = 2

• Crystal Data
  • Cubic
  • Point Group: 43m
  • As tetrahedra, dodecahedra, and pseudo-octahedral crystals, up to 12cm
  • As rounded grains
  • X-ray powder pattern: 3.382 (100), 1.955 (80), 2.215 (70), 2.618 (65), 1.692 (65), 1.510 (50), 1.466 (50)

• Chemical Composition

  Elements	Content 1	Content 2	Content 3
  MnO	52.48	24.34	51.12
  SiO2	31.06	29.62	32.47
  BeO	[13.52]	[13.21]	13.52
  S	5.51	5.91	5.78
  -O = S	[2.75]	[2.95]	2.89
  ZnO	0.55	16.09
  Al2O3	0.30	0.03
  FeO	0.18	13.25
  CaO	0.07
  Total	[100.85]	[99.57]	100.00

• Optical Properties
  • Optical Class: Isotropic
  • n = 1.728-1.749

• Estimated Properties

  Electron density	Bulk density (electron density) = 3.12 g/cm3 note: Specific gravity of Helvine = 3.26 g/cm3
  Photoelectric	PEHelvine = 11.15 barns/electron U = PEHelvine x ρElectron density = 34.82 barns/cm3
  Fermion index	Fermion index = 0.05 Boson index = 0.95
  Radioactivity	Helvine is not radioactive

How to Identify Helvine

Helvine can be identified from its brown, yellow, or gray color forms. It has a transparent to opaque appearance. It is fluorescent, with a grayish-white streak, a vitreous luster, and indistinct cleavages. Its fractures are brittle and its crystals are massive.

The average density of helvine is 3.26 g/cm³, and its relative hardness ranges from 6 to 6.5.

Global Distribution

Helvine is distributed in the following places:

• Schwarzenberg and Breitenbrunn, Saxony, Germany
• Yxsjo, Orebro, Sweden
• Luppikko, Karelia
• Miass, Ilmen Mountains, Southern Ural Mountains, Russia
• Inyl'chek Mountains, Tien Shan, south-eastern Kyrgyzstan
• Kara-Oba, Kazakhstan
• Langesundsfjord, at Hortekollen
• PitkÄaranta, Finland
• Silver Bow Co. at Butte, Montana
• Amelia, Amelia Co. Virginia
• American Tunnel, Silverton, San Juan Co. Colorado
• Benedict Creek, Sawtooth Mountains, Boise Co. Idaho
• Clark vein, Rincon, San Diego Co. California
• Iron Mountain, Sierra Co. New Mexico
• Hongo mine, Iwate Prefecture
• Oashi mine, Tochigi Prefecture
• Yagisawa mine, Nagano Prefecture

Occurrence of Helvine and Useful Mineral Association

Helvine occurs in gneisses, granite pegmatites, granites, skarns, and contact zones.

It is associated with vesuvianite, diopside, chlorite, fluorite, magnetite, and garnet.

References

• http://rruff.geo.arizona.edu/doclib/hom/helvine.pdf
• http://www.mindat.org/min-1855.html
• http://webmineral.com/data/Helvite.shtml