MANGANO CALCITE PYRITE
Lovely Pyrite Mangano Calcite Couple. Two specimens from the same location were in an old stock box and here they are. One in a triangle crystal shape with mass coating of micro Pyrite on one side. Another light coloured crystals cluster with minor Micro Pyrite. Both of these specimens are fluorescent under the long and short of it. UVC and UVA, just for good measure a few pics showing very brief phosphorescence with a UV laser. Just the kind many crystal lovers choose over more perfect collectible pieces. A super nice piece and something different from the more commonly available.
Broken Hill, New South Wales, Australia.
6.6cm x 4.8cm x 2.7cm, 86g.
6cm x 4.6cm x 2.3cm, 58g.
Mangano Calcite: (Ca,Mn)CO3.
Pyrite is the classic “Fool’s Gold”. There are other shiny brassy yellow minerals, but pyrite is by far the most common and the most often mistaken for gold. Whether it is the golden look or something else, pyrite is a favorite among rock collectors. It can have a beautiful luster and interesting crystals. It is so common in the earth’s crust that it is found in almost every possible environment, hence it has a vast number of forms and varieties.
Bravoite is the name given to a nickel-rich iron sulfide. It is closely related to pyrite but contains up to 20% nickel. Some mineral books treat it as a variety of pyrite. Pyrite is a polymorph of marcasite, which means that it has the same chemistry, FeS2, as marcasite; but a different structure and therefore different symmetry and crystal shapes. Pyrite is difficult to distinguish from marcasite when a lack of clear indicators exists.
Pyrite’s structure is analogous to galena’s structure with a formula of PbS. Galena though has a higher symmetry. The difference between the two structures is that the single sulfur of galena is replaced by a pair of sulfurs in pyrite. The sulfur pair are covalently bonded together in essentially an elemental bond. This pair disrupts the four fold symmetry that a single atom of sulfur would have preserved and thus gives pyrite a lower symmetry than galena. We have sold the Disc form called Pyrite Sun, Spheres formed of hundreds of squares, Cubes of near square, Octahedral crystal form and crystal cluster forms.
Although pyrite is common and contains a high percentage of iron, it has never been used as a significant source of iron. Iron oxides such as hematite and magnetite, are the primary iron ores. The metal is not as economical as these ores possibly due to their tendency to form larger concentrations of more easily mined material. Pyrite would be a potential source of iron if these ores should become scarce.