Aquamarine on Black Tourmaline - Erongo Mountains, Namibia

A lone, pale blue aquamarine crystal sits atop a lusterous, well-terminated chunk of schorl from the Erongo Mountains in Namibia. Although the schorl has broken away from the host rock, the crystal is in overall good shape, and displays nicely on a flat surface.

Beryl is a mineral that's composed of beryllium aluminum cyclosilicate, with the chemical formula Be3Al2(SiO3)6. Naturally occurring beryl tends to form hexagonal crystals that can reach several meters in size if given the right conditions. Completely pure beryl will be transparent and colorless, while mineral impurities frequently tint the crystals color in most specimens.

Well known varieties of beryl include aquamarine and emerald, although beryl can also be green, blue, yellow, white and red, depending on the incorporated impurities during formation. Red beryl is known to be the most rare form of beryl found and is currently only known to be found in New Mexico and Utah.
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.
DETAILS
SPECIES
Aquamarine, Tourmaline
LOCATION
Erongo Mountains, Namibia
SIZE
Aquamarine is .39x.25" on 2x1.59x1.29" Schorl
CATEGORY
ITEM
#31878