The articles in this category are forms of Quartz.
“Onyx is a cryptocrystalline form of quartz. The colors of its bands range from white to near...Onyx
“Amethyst is a violet variety of quartz. It is the birthstone of February. In acient times...Amethyst
“Aventurine is a bluish variety of Quartz. It is composed of different materials, giving it its...Aventurine
“Coesite is a form of silicon dioxide that is formed when high pressure and temperatures of over...Coesite