Complex borosilicate mineral group with extreme compositional variation. Shows strong pleochroism and piezoelectric properties. Color: Black schorl , pink, green, blue, watermelon. Luster: Vitreous. Streak: White. Cleavage: None conchoidal fracture. Hardness: 7-7.5. Transparency: Transparent to opaque. Crystal system: Hexagonal Trigonal. Chemical formula: Complex borosilicate. Specific gravity: 2.82-3.32. Formation: Crystallizes in granitic pegmatites and some metamorphic rocks; schorl black is most common variety. Common geological settings: Brazil, Afghanistan, Mozambique, USA; found in pegmatites and metamorphic rocks. Common look-alikes and related entries: Hornblende, Augite, Schorl.
These authoritative resources support category-level nomenclature, terminology, identification methods, and safety. When a specimen-specific safety warning appears, the public-health source listed here directly supports that precaution. They are not line-by-line citations for every other property on this entry, and natural specimens vary.
Editorial owner
GeoMiner
Last updated
2026-03-30T14:36:55.836857+00:00
Review status
Published; not independently peer-reviewed
IMA–CNMNC List of Mineral Names — International Mineralogical Association. Official mineral-name, nomenclature, and classification records.
Mineral ID Key — Mineralogical Society of America. Physical-property identification methods, repeat-testing guidance, and limitations.
Complex borosilicate mineral group with extreme compositional variation. Shows strong pleochroism and piezoelectric properties.
How can you identify Tourmaline?
Compare several properties rather than relying on colour alone. This entry records colour: Black schorl , pink, green, blue, watermelon; lustre: Vitreous; streak: White; Mohs hardness: 7-7.5; cleavage: None conchoidal fracture; crystal system: Hexagonal Trigonal; transparency: Transparent to opaque. Confirm an important identification with additional field tests or qualified laboratory work.
How does Tourmaline form?
Crystallizes in granitic pegmatites and some metamorphic rocks; schorl black is most common variety.
Where is Tourmaline commonly found?
Brazil, Afghanistan, Mozambique, USA; found in pegmatites and metamorphic rocks.
What is Tourmaline commonly confused with?
Tourmaline may be confused with Hornblende, Augite, Schorl. Compare multiple diagnostic properties because colour and surface appearance can overlap.
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