mineral

Polished black-and-white banded stone, likely tourmalinated quartz or zebra jasper

Quartz (SiO₂) with black tourmaline (schorl, NaFe₃Al₆(BO₃)₃Si₆O₁₈(OH)₄), or quartz-rich zebra jasper

AI-generated identification · may be incorrect

Hardness about 7 for quartz; black vitreous areas contrast with white-gray bands, and the polished surface has a glassy luster. Quartz is trigonal and lacks cleavage; tourmaline is trigonal with poor cleavage. The photo cannot distinguish the alternatives conclusively.

Identified August 12, 2026More mineral →

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At a glance

Common name: Polished black-and-white banded stone, likely tourmalinated quartz or zebra jasper
Scientific name: Quartz (SiO₂) with black tourmaline (schorl, NaFe₃Al₆(BO₃)₃Si₆O₁₈(OH)₄), or quartz-rich zebra jasper
Category: mineral
Identified: August 12, 2026
Method: Standard

AI Estimated Value

Typically $5-$25 for a small polished specimen; approximately $30-$100 for larger, sharply patterned or high-quality pieces.

Not an official valuation

AI estimate for general interest only — not an appraisal. Actual value depends on condition, provenance, and market demand. Verify with a professional before buying, selling, or insuring.

This identification was generated by AI and may contain errors. Verify important details before relying on them — and never use an AI result to judge whether a specimen is safe to handle. Read the full disclaimer

Physical properties

Formation & geological history

Quartz-tourmaline material forms in hydrothermal veins and pegmatites as silica-rich fluids crystallize; zebra jasper forms through silica-rich sedimentary or volcanic alteration. Ages vary widely by locality, commonly Paleozoic to Precambrian.

Uses & applications

Cut and polished mainly for cabochons, carvings, worry stones, and decorative objects; attractive pieces are used in low-cost jewelry and mineral collections.

Geological facts

Tourmalinated quartz contains needle-like black schorl inclusions, whereas zebra jasper typically shows opaque, diffuse black-and-white swirls or bands and is generally softer.

Field identification & locations

Look for transparent or translucent quartz enclosing sharp black needles to confirm tourmalinated quartz; opaque, uniformly banded material suggests zebra jasper. Common sources include Brazil, Madagascar, India, and Uruguay.