|(Mn 2+ )SiO 3|
Massive black Pyrolusite.
Along with rhodochrosite, it is the main manganese ore, the extraction of which is carried out by electrolysis. Manganese is a strategically highly valued metal, as it is a component of steel and other alloys such as manganese-bronze.
It is also used for the manufacture of chlorine and disinfectants. It is also used to discolor glass, because when it is mixed with molten glass, ferrous iron is oxidized to ferric iron, thus the greenish and brown colors that the glass would have disappear.
It is also used as a coloring material in the manufacture of paints as well as in tiles and ceramics.
The mineral includes a label with the name and origin and is attached to a cardboard box. 4 cm square.
*The price is per unit (a single cardboard box of the four shown in the photo)
Since the minerals are natural, you will receive a piece similar to the one in the photograph. The minerals come in cardboard boxes and are glued to a porex base with hot silicone; these can be removed using ethyl alcohol without damaging the mineral. The size is approximate.