Greenockite

Field of view: 30 mm. A crust-like group of greenockite. The powdery yellow crust is greenockite. The white host is quartz. The silver-gray grains exhibiting perfecte cleavage at the upper left, for example, are sphalerite. The brown parts at the upper left is limonite.

Recovered from a quartz vein in a meteoric oxidation zone of a moderate-temperature hydrothermal deposit combined with skarn formed by contact metamorphism of I-type (magnetite-series) granite associated with a caldera complex.

Greenockite from this location was described in 1952.

Sphalerite generally contains minor amount of Cd replacing Zn, and Cd is concentrated as greenockite in the weathering process by oxidation of Zn-bearing minerals. Artificial Cd is also produced as a by-product of Zn rment.