1.8" Sunshine Cactus Quartz Crystal - South Africa
This is a beautiful orange cactus quartz cluster from the Magaliesberg Mountains of South Africa. There is some purple coloration near the tip of the crystal (quartz var. amethyst). It has a unique orange/yellow coloration due to the presence of iron oxides.
Cactus quartz, often also referred to as spirit quartz, is a variety of quartz characterized by second-generation druzy crystals growing on the faces of larger quartz crystals. The small second-generation crystals point away from the prism and their orientation is not related to the crystallographic orientation of the central crystal. Cactus quartz is currently only known from the Magaliesberg Mountains region of South Africa, and comes in a variety of shades ranging from white to deep purple to orange colorations. The deep purple amethyst points are the rarest and most coveted by collectors.
Silicon Dioxide, also know as SiO2 or Quartz, is the second most abundant mineral in the Earth's crust. Quartz crystals generally grow in silica-rich, hot watery solutions called hydrothermal environments, at temperatures between 100°C and 450°C, and usually under very high pressure. Quartz veins are formed when open fissures are filled with hot water during the closing stages of mountains forming, and can be hundreds of millions of years old.
Amethyst is a purple variety of quartz (SiO2) and owes its violet color to natural irradiation, iron impurities, and the presence of trace elements, which result in complex crystal lattice substitutions. It’s considered a semi-precious gemstone, and just two centuries ago was considered to have a value on par with diamonds, sapphires and rubies. The largest and best known amethyst deposits occur in southern Brazil and Uruguay but many localities around the world produce an amazing variety of amethyst crystals and formations.