Helvine (also known as Helvite) (inclusions in Quartz)
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Helvine is named from the Greek word helvus for yellow or sun, in allusion to its typical color. The IMA officially recognized name (2012 IMA list) is Helvine, not Helvite, although the synonym Helvite may be more common in collections and literature.

Discovered in 1804; IMA status: Valid (pre-IMA; Grandfathered)

Chemistry

Chemical Formula:

Mn²⁺₄Be₃(SiO₄)₃S

Manganese Beryllium Silicate Sulfide

Molecular Weight:

555.10 gm

Composition:

Manganese

39.59 %

Mn

51.12 %

MnO

Beryllium

4.87 %

Be

13.52 %

BeO

Silicon

15.18 %

Si

32.47 %

SiO₂

Sulfur

5.78 %

S

5.78 %

S^2-

—

 —  %

S

-O=S

Oxygen

34.59 %

O

100.00 %

100.00 %

= TOTAL OXIDE

Classification

Mineral Classification:

Silicates (Germanates)

Strunz 8th Ed. ID:

8/J.12-20

Nickel-Strunz 10th Ed. ID:

9.FB.10

9 : SILICATES (Germanates)
F : Tektosilicates without zeolitic H₂O
B : Tektosilicates with additional anions

Related to:

Helvine Group. Danalite-Helvine Series. Genthelvite-Helvine Series.

Members of Group:

Helvine Group: Danalite, Genthelvite, Helvine, Tugtupite

Varieties:

None

Synonyms:

Helvite, Moonlight Garnet, Tetrahedral Garnet

Crystal Data

Crystallography:

Isometric - Hextetrahedral

Crystal Habit:

As tetrahedra, dodecahedra, and pseudo-octahedral crystals, up to 12 cm; as rounded grains.

Twinning:

None

Physical Properties

Cleavage:

Distinct on {111} 

Fracture:

Irregular/Uneven, Sub Conchoidal

Tenacity:

Brittle

Moh's Hardness:

6.0 - 6.5; VHN = 741 - 873

Density:

3.20 - 3.44 (g/cm³)

Luminescence:

None

Radioactivity:

Not Radioactive

Other:

Pyroelectric

Optical Properties

Color:

Yellow, brown, red, gray-yellow, yellow-green

Transparency:

Translucent

Luster:

Vitreous to Resinous

Refractive Index:

1.728 - 1.749  Isotropic

Birefringence:

0.000 - Isotropic minerals have no birefringence

Dispersion:

n/a

Pleochroism:

None

Occurances

Geological Setting:

May be locally abundant in granites, granite pegmatites, gneisses, and contact zones and skarns.

Common Associations:

Garnet, Magnetite, Fluorite, Chlorite, Diopside, Vesuvianite

Common Impurities:

Al, Fe, Zn, Ca

Co-type Localities:

• Brüder Lorenz Mine, Breitenbrunn, Breitenbrunn District, Erzgebirge, Saxony, Germany
• Friedefürst Mine, Breitenbrunn, Breitenbrunn District, Erzgebirge, Saxony, Germany

Year Discovered:

1804

View mineral photos:

Helvine Mineral Photos and Locations

More Information

Mindat.org
Webmineral.com

Helvine, also known as Helvite, is a rare manganese silicate sulfide mineral that is a member of the Helvine Group of minerals that also includes Danalite, Genthelvite, Helvine  and Tugtupite. Helvine is also considered to be a Feldspathoid. Minerals with chemistries that are close to those of the alkalai Feldspars, but are poor in silica (SiO2) content, are called Feldspathoids. Helvine is named from the Greek word 'helvus' for yellow or sun, in allusion to its color. The IMA officially recognized name (2012 IMA list) is Helvine, not Helvite, although the synonym Helvite may be more common in collections and literature. Helvine can be found in colors of yellow, pink, reddish brown or red, grayish yellow and yellowish green. Faceted Helvine gems are very rare and usually small but fairly lage Quartz gems with Helvine crystal inclusions are occassionally available. One thing that Helvine and Quartz have in common is that they are both Pyroelectric. Pyroelectricity is the ability of certain mineral crystals to generate an electrical potential when they are heated or cooled.

Helvine can be found at the following localities: from Schwarzenberg and Breitenbrunn, Saxony, Germany. Exceptionally large crystals from Yxsjö, Örebro, Sweden. At Luppikko, Karelia. In Russia, near Miass, Ilmen Mountains, Southern Ural Mountains. From the Inyl'chek Mountains, Tien Shan, southeastern Kyrgyzstan. At Kara-Oba, Kazakhstan. From the Langesundsfjord, at Hørtekollen, and several other localities in Norway. In Finland, at Pitkäranta. In the USA, at Butte, Silver Bow County, Montana; from Amelia, Amelia County, Virginia; in the American Tunnel, Silverton, San Juan County, Colorado; on the east fork of Benedict Creek, Sawtooth Mountains, Boise County, Idaho; from the Clark vein, Rincon, San Diego County, California; at Iron Mountain, Sierra County, New Mexico. At the Navegadora Mine (Navegador Mine; Orozimbo Mine), Penha do Norte, Conselheiro Pena, Doce valley, Minas Gerais, Brazil. In China at Tongbei, Yunxiao County, Zhangzhou Prefecture, Fujian Province. In the Hongo mine, Iwate Prefecture; the Oashi mine, Tochigi Prefecture; the Yagisawa mine, Nagano Prefecture; and several other places in Japan. In the Kara #1 Pit, Kara Mines, Hampshire district, Tasmania, Australia. A few additional localities are known.
 

  
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