igneous

Schorl (Black Tourmaline) in Quartz or Feldspar Matrix

NaFe3Al6(BO3)3Si6O18(OH)4 (Schorl) in Granitic Pegmatite

Hardness: 7-7.5 (Tourmaline) / 6-7 (Matrix). Color: Jet black needle-like crystals in a tan/white matrix. Luster: Vitreous to resinous. Crystal structure: Trigonal (hexagonal prisms). Cleavage: None/Indistinct.

Hardness: 7-7
Color: Jet black needle-like crystals in a tan/white matrix
Luster: Vitreous to resinous

Identified March 8, 2026More igneous →

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Physical properties

Formation & geological history

Formed in granitic pegmatites during the final stages of magma crystallization. Rich in boron; found in intrusive igneous environments typically ranging from Proterozoic to Cenozoic eras.

Uses & applications

Commonly used for mineral collecting and as a 'healing crystal' in metaphysical circles. Historically used as a source of boron; high-quality specimens may be used as cabochons in jewelry.

Geological facts

Tourmaline is pyroelectric, meaning it generates an electrical charge when heated. It is also piezoelectric, generating a charge under mechanical stress. Schorl accounts for approximately 95% of all tourmaline found in nature.

Field identification & locations

Identify by the elongated, columnar, or needle-like black crystals embedded in light-colored rock. Look for vertical striations along the crystal faces. Common in Brazil, Namibia, and the USA (California/Maine).

Other igneous specimens

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Blue Apatite

Fluorapatite (Ca5(PO4)3F)

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Dark Igneous Rock (Likely Basalt or Diabase)

Basalt (extrusive igneous rock) or Diabase (intrusive igneous rock - also known as Dolerite), largely composed of plagioclase feldspar, pyroxene (augite), and sometimes olivine and amphibole. Exact mineralogy would require thin section analysis.

Igneous

Magnetite

Iron(II,III) oxide (Fe3O4)

mineral

Sodalite

Sodalite - Na8(Al6Si6O24)Cl2

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Blue Apatite

Apatite (Group), Ca5(PO4)3(F,Cl,OH)

mineral

Magnetite

Magnetite (Fe3O4)

mineral