mineral

Black Tourmaline (Schorl) or Obsidian Bead

Complex sodium iron borosilicate, NaFe3+3Al6(BO3)3Si6O18(OH)4 (or Volcanic amorphous silicate glass)

AI-generated identification · may be incorrect

Hardness: 7-7.5 (if tourmaline) or 5-5.5 (if obsidian); Color: Jet black, opaque to deeply translucent; Luster: Vitreous to sub-metallic; Crystal Structure: Trigonal (hexagonal system) or Amorphous; Specific Gravity: 2.8-3.2

Hardness: 7-7
Color: Jet black, opaque to deeply translucent
Luster: Vitreous to sub-metallic

Identified October 15, 2026More mineral →

Explore Black Tourmaline (Schorl) or Obsidian Bead in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Formation & geological history

Tourmaline typically crystallizes in granitic pegmatites and metamorphic rocks rich in boron through hydrothermal fluids. Obsidian forms from rapidly cooled felsic lava.

Uses & applications

Commonly shaped and polished into spherical beads for jewelry, bracelets, rosaries, or collected for holistic and metaphysical grounding practices.

Geological facts

Black tourmaline (schorl) represents roughly 95% of all natural tourmaline found in the world. It is known to possess pyroelectric and piezoelectric properties, generating an electric charge when heated or compressed.

Field identification & locations

Found widely in pegmatite fields worldwide, including Brazil, Madagascar, and parts of the United States. It can be distinguished from black glass or jet by its higher density, hardness, and vitreous reflection.