The finest small cabinet Cavansite twin I have ever seen. Stunning twin Cavansite crystals overgrew the Heulandite on this spectacular piece from the legendary Wagholi Quarries, Pune, Maharashtra, India (2016).
Amethyst is a purple variety of quartz (SiO2) and owes its violet colour 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. Popular for its purple colouring it is used for...