gemstone

Red corundum (ruby) crystal fragment

Corundum, Al₂O₃; ruby is red corundum colored mainly by chromium

AI-generated identification · may be incorrect

The small vivid-red fragment appears translucent with a vitreous luster, but the photo is insufficient to confirm its identity. Corundum has Mohs hardness 9, a trigonal crystal structure, no true cleavage, and specific gravity around 4.0.

Identified September 27, 2026More gemstone →

Explore Red corundum (ruby) crystal fragment 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: Red corundum (ruby) crystal fragment
Scientific name: Corundum, Al₂O₃; ruby is red corundum colored mainly by chromium
Category: gemstone
Identified: September 27, 2026
Method: Standard

AI Estimated Value

Unverified small fragment: roughly $1–$50; a confirmed natural, gem-quality ruby may be worth far more, depending on size, clarity, treatment, and origin.

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

Natural ruby forms in aluminum-rich, silica-poor metamorphic rocks or in some igneous settings; gem deposits range from ancient to geologically recent. A red fragment may also be synthetic or treated.

Uses & applications

Rubies are cut for jewelry and collected; corundum is also used as an abrasive and in hard-wearing components.

Geological facts

Ruby and sapphire are varieties of the same mineral, corundum; trace elements determine color.

Field identification & locations

Check for hardness, crystal form, and diagnostic inclusions, but these require testing; red glass or synthetic corundum can look similar. Natural rubies occur in Myanmar, Mozambique, Sri Lanka, Thailand, and elsewhere.