Geocronite - Encyclopedia
Class : Sulfides and sulfosalts
Subclass : Sulfosalts
Crystal system : Monoclinic
Chemistry : Pb14(Sb,As)6S23
Rarity : Uncommon
Geocronite is an uncommon lead sulfoantimonide, occurring in low-temperature hydrothermal veins along with galena, sphalerite, pyrite, tetrahedrite and barite. It forms a continuous series with jordanite, its arseniferous equivalent. It takes its name from the Greek gê (Earth) and Cronos (Saturn), ancient alchemy terms designating antimony and lead. Geocronite gives rare tabular crystals, sometimes large (9 cm), commonly twinned in sectors, and grainy to earthy masses of lead gray to grayish color.
Main photo : 6.5 cm geocronite Pollone Mine, Tuscany, Italy © Marco Barsanti
Geocronite in the World
Twinning
Twin is known on {001}, it can be multiple and form stars.
Fakes and treatments
No fakes recorded for this mineral species.
Hardness : 2.5 to 3
Density : 6.46
Fracture : Irregular
Streak : Gray
TP : Opaque
RI : -
Birefringence : -
Optical character : -
Pleochroism : None
Fluorescence : None
Solubility : Hydrochloric acid
Magnetism : None
Radioactivity : None