Black tourmaline, also known as schorl, is the most common variety of the borosilicate mineral tourmaline, deriving its deep black color from high iron content within the crystal structure, making it one of the most abundant and recognizable tourmaline varieties. This opaque to translucent gemstone forms long, striated prismatic crystals with distinctive vertical ridging along their length, creating a natural texture that is both visually striking and tactilely interesting. Black tourmaline has been valued since ancient times for both its protective qualities and its piezoelectric properties, which generate electrical charges when heated or under pressure, making it useful in both metaphysical and scientific applications.
- Color range: Deep black to brownish-black; occasionally shows very dark green or blue undertones in thin sections or edges
- Sizes: Available from small rough crystals (1-2cm) to large specimen pieces (several feet in length); dramatic size range possible
- Shapes: Naturally occurs as long prismatic crystals with vertical striations; also available as tumbled stones, beads, and carved pieces
- Origin: Worldwide including Brazil, Madagascar, Africa, and Maine; Brazil produces some of the finest quality specimens
- Hardness: 7 to 7.5 on Mohs scale, excellent durability making it suitable for all jewelry applications and decorative uses
- Crystal structure: Distinctive vertical striations and prismatic form; natural crystals show remarkable geometric precision
- Luster: Vitreous to sub-metallic luster when polished; raw specimens show more subdued natural surface appearance
- Piezoelectric properties: Generates electrical charges when heated or compressed, making it scientifically as well as metaphysically interesting
