mineral

Quartz geode (likely iron-stained amethyst/citrine)

Silica geode; crystalline quartz, SiO₂, with iron-oxide staining and possible amethyst/citrine

AI-generated identification · may be incorrect

Hardness 7 Mohs; white to gray quartz crystals with rusty red-brown iron staining and locally smoky purple/yellow tones; vitreous luster, hexagonal crystals, and no prominent cleavage. The specimen appears cut or broken open, exposing a drusy crystal-lined cavity.

Identified September 19, 2026More mineral →

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At a glance

Common name: Quartz geode (likely iron-stained amethyst/citrine)
Scientific name: Silica geode; crystalline quartz, SiO₂, with iron-oxide staining and possible amethyst/citrine
Category: mineral
Identified: September 19, 2026
Method: Standard

AI Estimated Value

Approximately $10–$50 for a common small specimen; $50–$150 or more if crystals are unusually colorful, large, or well displayed.

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

Forms when silica-rich groundwater deposits quartz crystals inside a gas cavity or vug, commonly in volcanic basalt; later oxidation produces the red-brown staining. Exact geological age cannot be determined from the photograph; such geodes commonly form in Cenozoic volcanic rocks.

Uses & applications

Used as a decorative and collecting specimen; amethyst varieties are also used in jewelry. Value is primarily ornamental rather than industrial.

Geological facts

The exterior is typically tougher, fine-grained chalcedony, while the interior grows inward-facing quartz crystals. Iron impurities can create orange, red, and brown colors and may obscure true amethyst coloration.

Field identification & locations

Look for a hollow or partially hollow rounded nodule, chalcedony rind, and radiating quartz crystals that scratch glass. Common sources include Brazil, Uruguay, Mexico, and the western United States; identification would be improved by testing hardness and examining crystal color under strong light.