20139 - Beautiful Purple Natural Amethyst Crystals Cluster Minas Gerais District - Brazil Cobaltoan calcite Nopcsa 1928

Nopcsa 1928

This species was described by Lavocat (1954)

Africa and North America

Its size is enormous compared to the specimens that are usually found in this taxon

This type of turtle remains in the Cretaceous are very rare

20139 - Beautiful Purple Natural Amethyst Crystals Cluster Minas Gerais District - Brazil Cobaltoan calcite Nopcsa 1928Amethyst is a purple variety of quartz (SiO2) and owes its violet color to irradiation, impurities of iron and in some cases other transition metals, and the presence of other trace elements, which result in complex crystal lattice substitutions. The hardness of the mineral is the same as quartz, thus making it suitable for use in jewelry.