PYRITE CRYSTALS RHODOCHROSITE
A great combo Pyrite Crystals Rhodochrosite. Solid, pastel pink Rhodochrosite covered in awesome Pyrite crystals. A really nice specimen.
3.0cm x 9.2cm x 5.5cm, 205g.
Named in 1813 by Johann Friedrich Ludwig Hausmann from the Greek “rose”, and “colouring”, referring to its colour.
Calcite Group. Calcite Rhodochrosite Series and Rhodochrosite Siderite Series. Commonly occurs as a primary gangue mineral in moderate to low temperature hydrothermal veins. Also in high temperature metasomatic deposits and sedimentary manganese deposits or as a late stage hydrothermal mineral in pegmatites, especially lithiophilite bearing ones.
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. Abundantly found in Earth’s crust, in almost every possible environment. In Plutonic, Volcanic, Sedimentary and Metamorphic rocks. Interestingly this Metal Sulfide has a vast number of forms and varieties. Disc form called Pyrite Sun, Spheres formed of hundreds of squares, Cubes of near perfect squares, Octahedral crystal form and crystal cluster forms.
The word Pyrite or Pyr means fire in Greek. It is piezoelectric which means when it is struck with metal or a hard rock it gives off sparks. This spark can start fires for cave men and cave women, shall we say cave people just in case. Pyrite was used as the strike on a gun to make the bullet fire in days of yore.
Bravoite is closely related 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. It is Dimorphic with Marcasite.
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 is; The single sulfur of galena is replaced by a pair of sulfurs in pyrite. This sulfur pair are covalently bonded together in an elemental bond. This pair disrupts the four fold symmetry that a single atom of sulfur would have preserved. This gives pyrite a lower symmetry than galena. The spelling of Sulfur can be Sulphur.
Striated, Cubic, Octahedral, Pyritohedral sometimes occurring as Twins (penetration is more than 50%) or Stacked (penetration is less than 50%). There are compact granular aggregates, Concretions, mammillated and stalactitic nodules. It’s hard stuff between 6 to 6.5 and heavy at 5. Enough said for a short description, below are Pyrite Mineral Specimen Images.