mineral

Black-and-white agate geode pendant

Agate (microcrystalline quartz, SiO₂), likely a hollow geode slice with chalcedony and drusy quartz

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; waxy to vitreous luster, concentric banding, black/gray chalcedony, and a pale crystalline cavity. Quartz is trigonal, with no cleavage; the rim appears gold-plated and human-made.

Identified August 18, 2026More mineral →

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At a glance

Common name: Black-and-white agate geode pendant
Scientific name: Agate (microcrystalline quartz, SiO₂), likely a hollow geode slice with chalcedony and drusy quartz
Category: mineral
Identified: August 18, 2026
Method: Standard

AI Estimated Value

Approximately $15–$60 for a typical plated pendant; $75–$200+ for larger, natural, well-banded specimens with attractive drusy crystals.

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 fills cavities in volcanic rock, depositing layered chalcedony and later quartz crystals. Agate formation commonly occurred from the Paleozoic through Cenozoic eras, depending on locality.

Uses & applications

Used for pendants, cabochons, carvings, ornaments, and lapidary pieces; this example is jewelry-grade mainly for its contrasting banding and geode cavity.

Geological facts

Agate’s bands often record successive changes in groundwater chemistry. Black coloration may be natural manganese/iron-related material or enhancement, and the metal setting is not geological.

Field identification & locations

Identify by translucent chalcedony, curved banding, conchoidal fracture, and hardness sufficient to scratch glass; avoid confusing it with dyed glass or resin. Common sources include Brazil, Uruguay, Mexico, India, and Madagascar.