Mineral Species: Magnesite var. Breunnerite 

Chemical Formula: (Mg,Fe)CO3

Chemical Name: Magnesium Iron Carbonate

Mineral Class: Carbonates

Mineral Notes: Breunnerite is an iron-rich variety of Magnesite with the Mg : Fe ratio ranging from 90 : 10 to 70 : 30. It was originally reported from Pfitsch pass, Zamser Grund (Zams valley), Ziller valley, North Tyrol, Tyrol, Austria and Großer Greiner Mt., Zemmgrund, Ziller valley, North Tyrol, Tyrol, Austria. However it is now know to occur elsewhere. The mineral is occasionally used in the manufacture of magnesia bricks.

Description: A matrix specimen formed almost entirely from crystalline Breunnerite. Nevertheless, individual crystals are easily seen as small flattened plates. The mineral has an attractive grey-green colour and a bright pearly luster. It also has a rather unusual greasy feel.

Location: Habachtal, Salzburg, Austria.