mineral

Quartz with iron-oxide staining, possibly associated with calcite

Quartz (SiO₂), with limonite/goethite (hydrated iron oxides) and probable calcite (CaCO₃)

AI-generated identification · may be incorrect

White to translucent, vitreous quartz crystals occur with yellow-orange earthy iron oxides and likely cream calcite. Quartz is Mohs 7, nonmetallic and lacks cleavage; calcite is Mohs 3 and effervesces in dilute hydrochloric acid. The specimen appears drusy and botryoidal rather than a single crystal.

Identified August 19, 2026More mineral →

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At a glance

Common name: Quartz with iron-oxide staining, possibly associated with calcite
Scientific name: Quartz (SiO₂), with limonite/goethite (hydrated iron oxides) and probable calcite (CaCO₃)
Category: mineral
Identified: August 19, 2026
Method: Standard

AI Estimated Value

About $5–$30 for a common hand specimen; $30–$100+ if crystals are unusually sharp, attractive, or locality-documented.

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

Likely formed when silica- and carbonate-rich hydrothermal fluids filled a cavity or fracture, followed by oxidation of iron-bearing minerals. Such mineralization is common in veins, vugs, and weathered sulfide deposits; age depends on its locality.

Uses & applications

Primarily a decorative or collecting specimen; quartz-bearing material may be used as aggregate or silica feedstock, but this small piece has no industrial significance.

Geological facts

The yellow-orange coating is probably limonite/goethite, whose color comes from oxidized iron. A vinegar test may weakly fizz if calcite is present, while quartz remains unaffected.

Field identification & locations

Common in hydrothermal veins, cavities, and oxidized ore zones worldwide, including Mexico, the United States, Brazil, and Morocco. Confirm quartz by hardness and glassy fracture; confirm calcite with acid and easy scratching.