6.8" Black Tourmaline (Schorl) Crystals with Orthoclase - Namibia

This is an association of orthoclase feldspar and black tourmaline (schorl), collected from the Erongo Mountains in Namibia. There are over 5 small aquamarine crystals on what could be considered the underside of the specimen. Under short wave UV light, the feldspar fluoresces a vibrant pink-red color.

Comes with an acrylic display stand.

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.

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.

Aquamarine is a blue-green variety of beryl. Oddly enough, it owes its color to iron(II) and iron(III) cations within the crystal lattice, of which iron(II) is responsible for the blue color, while iron(III) is responsible for the yellow color. The color vibrance and hue are dependent on the concentration of these cations, or lack of one or the other. The presence of both cations in the right position within the crystal lattice, can result in a deep blue colored crystal that is known as "maxixe".


FOR SALE
$225
DETAILS
SPECIES
Tourmaline var. Schorl, Beryl var. Aquamarine & Orthoclase Feldspar
LOCATION
Erongo Mountains, Namibia
SIZE
6.8 x 4.6"
CATEGORY
ITEM
#177554