Chemical Formula: SiO2

Chemical Name: Silicon Dioxide

Mineral Class: Tectosilicate

Mineral Notes: Amethyst is a variety of macrocrystalline Quartz displaying shades of violet due to the presence of small amounts of Fe3+ ions. The colour is usually strongest in the crystal terminations. It is a popular semi-precious gemstone. However the colour can fade in strong light. Interestingly heating can give rise to green, yellow and brown tones. 

Description: A very attractive little cluster of Amethyst consisting of an almost spherical aggregate of fused crystals. All have good terminations and form. The purple colour is most intense in the center of the cluster, with a gradual transition towards the outside of the specimen.

Location: Karur Mine, Tamil Nadu, India.