gemstone
Ruby
Corundum (Al2O3)
AI-generated identification · may be incorrectHardness: 9 on Mohs scale; Color: Deep red; Luster: Vitreous to sub-adamantine; Crystal Structure: Trigonal/Hexagonal; Specific Gravity: 3.97-4.05.
- Hardness
- 9 on Mohs scale
- Color
- Deep red
- Luster
- Vitreous to sub-adamantine
Identified More gemstone →
Explore Ruby in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 9 on Mohs scale; Color: Deep red; Luster: Vitreous to sub-adamantine; Crystal Structure: Trigonal/Hexagonal; Specific Gravity: 3.97-4.05.
Formation & geological history
Formed under intense heat and pressure in metamorphic rocks like marble or igneous rocks like basalt. Most fine specimens come from marble-hosted deposits where low silica allows for aluminum oxide formation stained by chromium.
Uses & applications
Primarily used in high-end jewelry, precision timepieces (bearings), and industrial lasers (ruby lasers).
Geological facts
Ruby is the red variety of the mineral corundum; every other color of corundum is known as sapphire. The presence of chromium is what gives ruby its signature red hue.
Field identification & locations
Identify by its extreme hardness (only diamond can scratch it) and intense red color. Commonly found in Myanmar, Thailand, Sri Lanka, and Madagascar. Natural rubies often contain needle-like inclusions known as 'silk'.
More like this
Other gemstone specimens
Gemstone Ring
N/A - Set piece of jewelry, likely Amethyst or Garnet with Diamond or CZ
gemstone
Ammolite
Ammolite (Biogenic Aragonite with trace elements; fossils of Placenticeras meeki and Placenticeras intercalare)
mineral
Diamond and Gold Jewelry
Carbon (Diamond) / Au (Gold)
gemstone
Red Jasper
Silicon Dioxide (SiO2) with Hematite inclusions
sedimentary
Amber
Succinite (Organic Gemstone)
mineral
Cubic Zirconia (simulant) or Diamond
ZrO2 (Cubic Zirconia) or C (Diamond)
gemstone