igneous

Quartz with Tourmaline and Iron Staining

Silicon Dioxide (SiO2) with Schorl (NaFe2+3Al6(Si6O18)(BO3)3(OH)3OH)

Hardness: 7 (Quartz) and 7-7.5 (Tourmaline). Color: Clear/white matrix, black crystals, orange-brown staining. Luster: Vitreous to greasy. Crystal Structure: Hexagonal/Trigonal. Cleavage: Indistinct/Conchoidal. Specific Gravity: 2.65-3.1.

Hardness: 7 (Quartz) and 7-7
Color: Clear/white matrix, black crystals, orange-brown staining
Luster: Vitreous to greasy

Identified May 12, 2026More igneous →

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Physical properties

Formation & geological history

Formed in an igneous pegmatite or hydrothermal vein environment where mineral-rich fluids cooled slowly, allowing large crystals to form. The orange staining is likely limonite or goethite from iron oxidation.

Uses & applications

Used primarily as decorative collector specimens. Quartz is used in electronics and glass-making; Tourmaline is used in jewelry and for its pyroelectric properties.

Geological facts

Black tourmaline, also known as Schorl, is the most common variety of tourmaline and was known as early as the 1400s in Saxony, Germany. The orange crust is a common weathering product of iron-bearing minerals.

Field identification & locations

Identify by its hardness (will scratch glass), the vitreous luster of the clear quartz, and the elongated, vertically striated black crystals typical of tourmaline schorl. Commonly found in granitic pegmatite regions.

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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