Mineral Species: Pyrolusite and Rhodochrosite

Chemical Formula: MnO2

Chemical Name: Manganese Oxide

Mineral Class: Oxide

Mineral Notes: Pyrolusite is one of the most common manganese minerals and is an important ore of this important industrial metal. The mineral is an oxidation product of other manganese species including Rhodochrosite, Rhodonite and Hausmannite. Pyrolusite belongs to a family of closely related manganese oxide minerals which are often found together and are difficult to distinguish. Often the group is commonly referred to as "wad". Pyrolusite has some interesting habits dispite its usual appearance as earthy black masses. Possibly its most famous form is its dendritic habit that forms fern-like patterns on the surfaces of rocks such as sandstone. These have often been mistaken for fossil plants.  

Description: A dark brown matrix which gradually becomes black towards the centre line. This represents the transition from host rock to very pure Pyrolusite. Unlike most specimens the Pyrolusite is highly crystalline and individual crystals can easily be seen when magnified. Over the surface are scattered tiny quartz crystals which provide a very aesthetic contrast. Also present are several spherical aggregates of very pale pink Rhodochrosite.

Location: Urkut, Hungary.