5.4" Aquamarine, Schorl & Orthoclase Feldspar Association - Namibia

This is a gorgeous specimen that contains aquamarine crystals and large black tourmaline (schorl) on orthoclase feldspar, collected from the Erongo Mountains in Namibia. The brown mineral on this specimen is a formation of goethite after siderite. This is a truly breathtaking mineral association.

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.

Orthoclase is a feldspar mineral with the chemical formula KAlSi₃O₈ and has a hardness of 6 - 6.5 on the Mohs hardness scale. It is considered a key component in many igneous rock formations and is one of the more abundant minerals throughout the continental crust. It can form individual crystals, however it's most commonly known for its pink coloration within granite rock. It has many commercial uses, including application in the production of a wide variety of ceramics and is sometimes used in the manufacturing of glass.

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.
FOR SALE
$950
DETAILS
SPECIES
Tourmaline var. Schorl, Beryl var. Aquamarine, Goethite & Feldspar (Orthoclase)
LOCATION
Erongo Mountains, Karibib, Erongo Region, Namibia
SIZE
5.4 x 4.2"
CATEGORY
ITEM
#132162