How to identify Ruby and Diamond Ring

To correctly identify Ruby and Diamond Ring (Corundum (Ruby) and Diamond), check each of these features in order. Many rocks and minerals look alike, so cross-reference multiple properties before deciding.

Step-by-step identification

1. 1

   Color

   Overall color and any zoning or banding

   Ruby: Red to purplish-red. Diamond: Colorless to various shades of yellow, brown, or rarely other colors (fancy colors).

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Ruby: Vitreous to adamantine. Diamond: Adamantine (the highest natural luster).

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Smooth, polished facets on cut gemstones. The metal setting will have its own characteristic texture.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Ruby: Typically cut into faceted shapes from hexagonal prismatic crystals. Diamond: Typically cut into brilliant, step, or mixed cuts from isometric (cubic) crystals.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   Ruby: No true cleavage, but exhibits parting along rhombohedral planes. Diamond: Perfect octahedral cleavage in four directions.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Rubies are found in metamorphic rocks (e.g., marble, gneiss, schist) and some igneous rocks (e.g., basalt). Diamonds are found in kimberlite and lamproite pipes, which are volcanic conduits that bring them from the mantle to the surface, and in alluvial deposits derived from these primary sources.

Key Facts

Hardness

Ruby (Corundum): 9 on Mohs scale. Diamond: 10 on Mohs scale (the hardest known natural material).

Specific Gravity

Ruby (Corundum): 3.97-4.05. Diamond: 3.50-3.53.

Crystal System

Ruby (Corundum): Trigonal. Diamond: Isometric (Cubic).

Color

Ruby: Red, purplish-red. Diamond: Colorless, yellow, brown, rarely other 'fancy' colors.

Luster

Ruby: Vitreous to adamantine. Diamond: Adamantine.

Transparency

Transparent to translucent (for both, gem quality is transparent).

Fracture

Ruby: Uneven to conchoidal. Diamond: Conchoidal.

Cleavage

Ruby: No true cleavage, but parting. Diamond: Perfect octahedral cleavage.

Composition

Ruby (Corundum): Aluminum oxide (Al2O3) with chromium (Cr) as the chromophore. Diamond: Pure carbon (C).

Physical characteristics

• Crystal Habit: Ruby: Typically prismatic, tabular, or rhombohedral. Diamond: Octahedral, dodecahedral, or cubic.
• Cleavage Type: Ruby: Parting on {0001} and {1011}. Diamond: Perfect on {111}.
• Fracture Type: Ruby: Uneven to conchoidal. Diamond: Conchoidal.
• Tenacity: Ruby: Brittle. Diamond: Brittle.
• Luster Type: Ruby: Vitreous to adamantine. Diamond: Adamantine.

Explore Ruby and Diamond Ring