The rock Itakolumite is a special, rare variety of quartzite, a metamorphically transformed sandstone under the influence of pressure and temperature. The binder, which holds the individual quartz grains together, consists of different layer silicates, mainly talc or chlorites, occasionally also sericide. In some varieties, the physical properties of the talcblades (low hardness, easy displaceability) necessitate the flexibility of the rock in thin plates (flexible or elastic sandstone, also known as articular quartz). With increasing content of layered silicates and decreasing quartz content, the itakolumite shows transitions to chlorite, talc and mica shards.
Itakolumit is found as a member of the Huronic (slate) formation especially in Brazil, where it is composed in Minas Gerais and Goiás high mountains and the named mountain Itacolomi (in the Serra do Espinhaço). In addition to its essential constituents, the rock here contains gold, brittle and brittle, accompanied by pyrite and arsenopyrite, hematite, magnetite, tourmaline, mica; it is occasionally interspersed with quartz veins, and the talc and chlorite slate occur in the form of a bearing. In Brazil, itacolumite is also the motherstone of diamonds. Otherwise the Itakolumit can be found in North and South Carolina (Sauratown Mountains), in the Urals and in Portugal.
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