KÖTTIGITE

    Class : Phosphates, arsenates, vanadates
    Subclass : Hydrated arsenates
    Crystal system : Monoclinic
    Chemistry : Zn3(AsO4)2 8H2O
    Rarity : Rare to very rare

Köttigite (or koettigite) is a zinc arsenate. It is a rare secondary mineral from the oxidation zone of zinc-arsenic deposits. It was named in honor of the German chemist Otto Köttig who provided the first description of the mineral. Köttigite constitutes small prismatic to acicular crystals frequently grouped in radiated tufts, fibrous crusts, or masses. Its color is closely dependent on its composition, from a colorless or white pure zinc pole, it changes to pale pink in cobalt-bearing varieties and to dark purplish blue (sometimes dark brown) in iron-rich varieties.

Main photo : Köttigite from Ojuela Mine, Mapimí, Durango, Mexico © Xia-Dong Xu

Köttigite from Clara Mine, Germany © Michael Förch
Köttigite from Ojuela Mine, Mapimí, Durango, Mexico © Marko Burkhardt
Köttigite from Jáchymov, Czech Republic © Bohuslav Bures
Köttigite from Jáchymov, Czech Republic © Bohuslav Bures

Köttigite in the World

The most beautiful specimens of köttigite come from the Ojuela mine, near Mapimi (Mexico), which yielded superb radiated groups of acicular crystals reaching 6 cm. Köttigite is also known in Pribram and Jachymov (Czech Republic), as well as in several veins in Germany (Schneeberg, Weiler, Wittichen...) and Namibia (Tsumeb). It is also reported in Sterling Hill (New Jersey).

Kornerupine in France

In France, köttigite is known in the mines of Orpierre (Hautes-Alpes) and Cap Garonne (Var).

Twinning

No twins known for this mineral species.

Fakes and treatments

No fakes recorded for this mineral species.


Hardness : 2.5 to 3
Density : 3.33
Fracture : Fibrous
Streak : Pink to white

TP : Translucent
RI : 1.622 to 1.671
Birefringence : 0.049
Optical character : Biaxial +
Pleochroism : Visible
Fluorescence : None

Solubility : Acids

Magnetism : NoneRadioactivity : None