2.2" Quartz Crystal with Black Tourmaline Inclusions - Namibia

Here is an interesting association of quartz var. amethyst and black tourmaline (schorl), collected from the Erongo Mountains in Namibia. The quartz is slightly purple at the termination, indicating it's more of an amethyst, as well as small segments containing smoky coloration. The quartz crystal also contains small, needle-like inclusions of schorl.

Tourmaline is a crystalline boron silicate mineral compounded with elements such as aluminium, iron, magnesium, sodium, lithium, or potassium. Schorl, or black tourmaline, is the most common form of tourmaline, and has been used for everything from jewelry to piezoelectric guitar pickups.

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 deposit occur in southern Brazil and Uruguay but many localities around the world produce an amazing variety of amethyst crystals and formations.

The color of smoky quartz results from free silicon, formed from the silicon dioxide by natural irradiation.

Tourmaline var. Schorl & Quartz var. Amethyst
Erongo Mountains, Namibia
2.2" wide