EULYTINE

    Class : Silicates
    Subclass : Nesosilicates
    Crystal system : Cubic
    Chemistry : Bi4(SiO4)3
    Rarity : Very rare

Eulytine (or eulytite) is the only known bismuth silicate. It is a very rare hydrothermal mineral, but nevertheless well represented in polymetallic veins. Its name comes from the Greek eu (good) and lusis (dissolution), due to its very low melting point. Eulytine is found in small tetrahedral crystals not exceeding 1 mm in bismuth-rich hydrothermal veins. It is yellowish-gray to grayish-white, green to bluish-green in color, sometimes straw yellow or brown, rarely colorless.

Main photo : Eulytine from Hechtsberg quarry, Hausach, Freiburg, Baden-Württemberg, Germany © Stephan Wolfsried

Eulytine from Johanngeorgenstadt, Saxony, Germany © Stephan Wolfsried
Eulytine from Heidenbach, Munster, Haut-Rhin, France © Thierry Brunsperger
Eulytine from Hechtsberg quarry, Hausach, Freiburg, Germany © Michael Förch
Eulytine of Schneeberg, Saxony, Germany © Volker Betz

Eulytine in the World

Eulytine is well represented in the polymetallic veins of Saxony in Germany (Johanngeorgenstadt, Schneeberg). The best specimens probably come from Buckbarrow Beck (Cumbria, England) where complex tetrahedra of 1 mm and spherical aggregates of 2 mm were discovered.

Eulytine in France

In France, eulytine is known in Ste-Marie-aux-Mines and Munster (Haut-Rhin), in Bussang and Faymont (Vosges) and in the mines of Costabonne (Pyrénées-Orientales).

Twinning

Twins are known on {001}.

Fakes and treatments

No fake listed for this mineral species.


Hardness : 4.5
Density : 6.1 to 6.6
Fracture : Irregular
Streak : White

TP : Translucent to transparent
RI : Not determined
Birefringence : 0
Optical character : None
Pleochroism : None
Fluorescence : None

Solubility : -


Magnetism : None
Radioactivity : None