20139 - Beautiful Purple Natural Amethyst Crystals Cluster Minas Gerais District - Brazil Cobaltoan calcite This type of turtle remains

This type of turtle remains in the Cretaceous are very rare

The matrix has some fractures that have been glued together

Nopcsa 1928

This species was described by Lavocat (1954)

20139 - Beautiful Purple Natural Amethyst Crystals Cluster Minas Gerais District - Brazil Cobaltoan calcite This type of turtle remainsAmethyst 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.