Schorl Tourmaline

NaFe2+3Al6(BO3)3Si6O18(OH)4 - Mohs Hardness: 6-6 1/2.  Schorl is best known as "Black Tourmaline". Although other forms of Tourmaline may be black, Schorl is exclusively black and, unlike other Tourmaline forms, is never transparent or even translucent.  Schorl is the most common form of Tourmaline. It may be highly lustrous and form in beautiful crystals, and is one of the most aesthetic black minerals known. It may form in tiny dense needles within a Quartz crystal where it is known as Tourmalinated Quartz.
Abstract/Description: NaFe2+3Al6(BO3)3Si6O18(OH)4 - Mohs Hardness: 6-6 1/2. Schorl is best known as "Black Tourmaline". Although other forms of Tourmaline may be black, Schorl is exclusively black and, unlike other Tourmaline forms, is never transparent or even translucent. Schorl is the most common form of Tourmaline. It may be highly lustrous and form in beautiful crystals, and is one of the most aesthetic black minerals known. It may form in tiny dense needles within a Quartz crystal where it is known as Tourmalinated Quartz.
Subject(s): Namibia, Africa
environmental sciences