mineral

Tumbled blue-gray stone, possibly chalcedony or quartzite

Likely microcrystalline quartz (SiO₂), but the image is insufficient for confident identification

AI-generated identification · may be incorrect

Smooth, rounded, polished surface; blue-gray to tan coloration with a dull-to-waxy luster. Quartz-based material has Mohs hardness about 7, no visible cleavage, and specific gravity near 2.6; translucency and hardness testing would help distinguish it from glass or other stone.

Identified August 26, 2026More mineral →

Explore Tumbled blue-gray stone, possibly chalcedony or quartzite in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

At a glance

Common name: Tumbled blue-gray stone, possibly chalcedony or quartzite
Scientific name: Likely microcrystalline quartz (SiO₂), but the image is insufficient for confident identification
Category: mineral
Identified: August 26, 2026
Method: Standard

AI Estimated Value

About $1-$10 for a common tumbled stone; roughly $10-$40 if unusually attractive, translucent, or confirmed as a desirable variety.

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

If chalcedony, it formed when silica-rich fluids filled cavities or fractures and precipitated as microcrystalline quartz, commonly in volcanic rocks. If quartzite, it is metamorphosed sandstone; age depends on its source locality.

Uses & applications

Typically used as a tumbled decorative stone, pocket specimen, or craft material; quality translucent examples may be used in inexpensive jewelry.

Geological facts

The blue-gray color may result from microscopic inclusions, staining, or surface treatment. A glassy appearance alone cannot reliably identify the material.

Field identification & locations

Common sources include Brazil, Madagascar, India, Uruguay, and the United States. Field tests: quartz should scratch glass and resist a steel knife; inspect for bubbles, which suggest glass, and use a specific-gravity or gemological test for confirmation.