MAZZITE

    Class : Silicates
    Subclass : Tectosilicates
    Crystal system : Hexagonal
    Chemistry : K2CaMg2(Si,Al)36O72 28H2O
    Rarity : Very rare

Mazzite belongs to the group of zeolites, of which it is one of the rarest representatives, known from only two sites in the world. It was described in 1974 from samples from Mont Sémiol near Montbrison (Loire, France), the type locality of another zeolite : offretite. It was named in honor of Fiorenzo Mazzi, Professor of Mineralogy at the University of Pavia (Italy). Mazzite forms fine colorless hexagonal needles ending in a pinacoid, generally millimetric but can exceptionally exceed a centimeter.

Main photo : Mazzite du Mont Semiol, Châtelneuf, Montbrison, Loire, France © Volker Betz

Mazzite in the World

The best specimens of mazzite come from the vacuoles of an olivine basalt from California, near boron, in spherolitic association with other zeolites (phillipsite, offretite) and carbonates (calcite, siderite) where mazzite needles can reach 15 mm.

Mazzite in France

In France, mazzite is known in fine colorless hexagonal needles 1.5 mm long and 20 µm in diameter at Mont Sémiol near Montbrison (Loire, France).

Right photo : Mazzite du Mont Semiol, Châtelneuf, Montbrison, Loire, France © Volker Betz

Twinning

No twin known for this mineral species.

Fakes and treatments

No fakes recorded for this mineral species.


Hardness : 4 to 5
Density : 2.11
Fracture : Undetermined
Streak : White

TP : Transparent
RI : 1.499 to 1.506
Birefringence : 0.007
Optical character : Uniaxial -
Pleochroism : None
Fluorescence : None

Solubility : -

Magnetism : NoneRadioactivity : None