mineral

Polished black stone bead, likely black tourmaline

Probably schorl (NaFe₃Al₆(BO₃)₃Si₆O₁₈(OH)₄); identification from the image is uncertain

AI-generated identification · may be incorrect

Small, polished, opaque black piece with a vitreous-to-waxy luster. If schorl, hardness is 7–7.5 Mohs and crystals are trigonal; the photo does not show diagnostic crystal form or cleavage.

Identified October 8, 2026More mineral →

Explore Polished black stone bead, likely black tourmaline in the encyclopedia →

Identify your own rocks.

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

App Store Google Play

Physical properties

Small, polished, opaque black piece with a vitreous-to-waxy luster. If schorl, hardness is 7–7.5 Mohs and crystals are trigonal; the photo does not show diagnostic crystal form or cleavage.

Formation & geological history

Tourmaline commonly crystallizes in boron-rich pegmatites and metamorphic rocks over a wide range of geological ages. The bead has been shaped and polished from natural material.

Uses & applications

Used for beads, jewelry, and mineral collecting; black tourmaline is also sold as a decorative stone.

Geological facts

Other black materials—including obsidian, onyx, and dyed stone—can look similar when polished.

Field identification & locations

Confirm by testing hardness and examining an unpolished surface or diagnostic crystal striations; commonly sourced from Brazil, Africa, and parts of North America. A single photo is insufficient for a confident species identification.