gemstone

Red synthetic corundum (ruby-colored lab-grown sapphire)

Corundum, aluminum oxide (Al₂O₃), likely synthetic and chromium-colored

AI-generated identification · may be incorrect

Mohs hardness 9; vivid red transparent body, vitreous luster, and trigonal crystal structure. The rectangular step/faceted cut shows strong reflections; natural ruby typically contains inclusions, while this clean appearance suggests laboratory material or glass imitation.

Identified August 10, 2026More gemstone →

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At a glance

Common name: Red synthetic corundum (ruby-colored lab-grown sapphire)
Scientific name: Corundum, aluminum oxide (Al₂O₃), likely synthetic and chromium-colored
Category: gemstone
Identified: August 10, 2026
Method: Standard

AI Estimated Value

About $5–$100 for common synthetic material; natural ruby of comparable appearance may range from $100 to over $10,000 depending on origin, clarity, treatment, and color.

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

Corundum crystallizes in aluminum-rich igneous or metamorphic rocks; gem rubies commonly form through metamorphism. Synthetic material is produced industrially by flame fusion or hydrothermal growth, with no geological age.

Uses & applications

Used as a ruby substitute in jewelry, ornamental objects, and precision optical or industrial applications. If confirmed natural ruby, value can be substantial; synthetic material is generally inexpensive.

Geological facts

Red corundum is ruby; other colors are called sapphire. Chromium produces the red color, and corundum is surpassed in hardness by diamond and moissanite.

Field identification & locations

Check for inclusions under magnification, curved growth lines, gas bubbles, and fluorescence; refractive index around 1.762–1.770 and specific gravity about 4.00 distinguish corundum from glass. A laboratory report is needed to establish natural origin and treatment.