1.53" Schorl with Smoky Quartz & Feldspar, Erongo Mountains

Here we have a gorgeous little matrix of schorl, smoky quartz, and feldspar from the Erongo Mountains in Namibia. Although the crystal has broken away from the original host rock, it displays nicely on a flat surface.

Schorl, also known as "black tourmaline" or "black schorl", is a black form of tourmaline that often occurs as lustrous prismatic crystals. The crystals can be stubby or elongated and typically feature striations that run along the length of the crystal. Many schorl crystals have flattened pyramidal terminations. They can also form in radiating, columnar and stalactitic aggregations, as well as small needle-like inclusions within quartz (tourmalinated quartz) and in massive form.

Schorl is a basic sodium iron aluminum boro-silicate and the generic chemical formula is NaFe2 + 3Al6(BO3)3Si6O18(OH)4 . It has been used for everything from jewelry to piezoelectric guitar pickups.
Feldspars are a group of rock-forming tectosilicate minerals. It is also one of the most common minerals on earth, making up nearly 60% of the crust.
Silicon Dioxide, also known 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.
Smoky quartz is a grey-brown to black variety of quartz. This common name is derived from from the appearance of smoke within the quartz crystal. Dependent on the location and the chemicals present during formation, smoky quartz can appear opaque black, however it’s typically translucent to some extent. It’s believed that the quartz gains this color from a combination of natural irradiation and aluminum impurities.
Smoky Quartz, Schorl & Feldspar
Erongo Mountains, Namibia