HELVINE

    Class : Silicates
    Subclass : Tectosilicates
    Crystal system : Cubic
    Chemistry : Mn4Be3(SiO4)3S
    Rarity : Quite common


Helvine (or helvite) is a complex silicate of beryllium and manganese which is found in various contexts : granites and their pegmatites, pegmatites of nepheline syenites, hydrothermal veins, tactites and skarns. It is a mineral which forms two continuous series : with genthelvite (zinciferous) and danalite (ferriferous). Its name comes from the Greek helios (sun) in reference to its main color. However, helvine is varied in color : gray-yellow to yellow and orange, brown-red, sometimes green-yellow. It essentially forms tetrahedra, sometimes pseudo-octahedra reaching up to 12 cm in edge and xenomorphic masses. It is very occasionally a beryllium ore.


Main photo : Helvine from Huanggang Mine, Inner Mongolia, China © Jordy Fabre

Helvine and spessatine from Wushan, Fujian, China © Martin Slama
Pseudo-octahedral helvine from Vevja Quarry, Tvedalen, Larvik, Norway © OT. Ljostad
Helvine from Jinlong Hill, Guangdong, China © Martin Slama
Twinned helvine from Glens Peak, Boise County, Idaho, USA © Eugene & Sharon Cisneros

Helvine in the World

Helvine is common in the United States, in mineralized veins such as Butte (Montana) or Sunnyside (Colorado), in often lithiniferous pegmatites such as Pala (California) or Foote (North Carolina), and in crystals in the magnetite, fluorite and garnet skarns of Iron Mountain (New Mexico). Magnificent brilliant 12 cm tetrahedra come from the Chingolo Mine, near Cosquin (Argentina) and large crystals from Yxsjö (Sweden). The pegmatites of Miass (Ouran, Russia) contain superb spherolitic clusters of helvite associated with topaz, phenakite and beryl. Mont St-Hilaire (Quabec, Canada) has rare small tetrahedral crystals. Finally, very beautiful orange tetrahedral crystals come from Chinese pegmatites from the spessartine mines of Wushan and Tongbei (Fujian), but also from Jinlong Hill (Guangdong) in gray to black tetrahedra on quartz, and from Huanggang Mines (Inner Mongolia).

Helvine in France

In France, helvine is known in the skarn of Costabonne (Pyrénées-Orientales) and it is also reported in Bagnères-de-Bigorre (Hautes-Pyrénées).

Twinning

Interpenetration twins are known for this mineral species.

Fakes and treatments

No fakes recorded for this mineral species, but very difficult to differentiate from genthelvite and danalite without chemical analysis.



Hardness : 6 to 6.5
Density : 3.2 to 3.44
Fracture : Irregular to conchoidal
Streak : White


TP : Translucent
RI : 1.728 to 1.749
Birefringence : 0
Optical character : None
Pleochroism : None
Fluorescence : None


Solubility : Hydrochloric acid

Magnetism : NoneRadioactivity : None