mineral

Moonstone with Black Tourmaline (Spiderweb Moonstone)

Feldspar (KAlSi3O8) with Schorl (NaFe3Al6(BO3)3Si6O18(OH)4)

AI-generated identification · may be incorrect

Hardness: 6-6.5 (Mohs scale); Color: Creamy white to grey with black web-like inclusions; Luster: Vitreous to pearly; Crystal structure: Monoclinic/Triclinic; Cleavage: Two directions at 90 degrees; SG: 2.56-2.59.

Hardness: 6-6
Color: Creamy white to grey with black web-like inclusions
Luster: Vitreous to pearly

Identified July 1, 2026More mineral →

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Physical properties

Formation & geological history

Formed in pegmatites and metamorphic rocks through slow cooling of magma, allowing the silica-rich feldspar to crystallize. The 'spiderweb' veins are caused by the intrusion of Tourmaline or other dark minerals during secondary geological events.

Uses & applications

Predominantly used for ornamental purposes, decorative obelisks, jewelry (cabochons), and by mineral collectors for its unique aesthetics and metaphysical associations.

Geological facts

Many specimens labeled as 'Spiderweb Moonstone' are actually varieties of Microcline or Orthoclase feldspar. The visual contrast between the pale matrix and dark inclusions is highly sought after in modern lapidary arts.

Field identification & locations

Identify by its distinctive play of light (adularescence) and the vein-like dark inclusions. Commonly sourced from Madagascar, India, and Sri Lanka. Collectors should look for polish quality and the contrast of the 'webbing'.