How to identify Diamond Simulant

To correctly identify Diamond Simulant (Cubic Zirconia or Moissanite (likely synthetic)), 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

   Typically colorless (D-F equivalent on diamond color scale), but can be produced in various colors.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Adamantine to sub-adamantine, often exhibiting a higher dispersion (fire) than natural diamond.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Smooth, faceted surfaces. No natural texture as they are cut and polished.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Cubic Zirconia crystallizes in the isometric (cubic) system. Moissanite crystallizes in the hexagonal system. Both are typically encountered as cut and polished gemstones, not in their raw crystal forms.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   Cubic Zirconia: Indistinct. Moissanite: Basal, indistinct. Neither exhibits the perfect octahedral cleavage of diamond.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Not found in natural geological environments. They are entirely products of laboratory synthesis.

Key Facts

Hardness

Cubic Zirconia: 8-8.5 on Mohs scale. Moissanite: 9.25 on Mohs scale.

Specific Gravity

Cubic Zirconia: 5.6-6.0. Moissanite: 3.22.

Crystal System

Cubic Zirconia: Isometric (cubic). Moissanite: Hexagonal.

Color

Colorless (most common), but can be produced in a wide range of colors.

Luster

Adamantine to sub-adamantine.

Transparency

Transparent.

Fracture

Conchoidal.

Cleavage

Cubic Zirconia: Indistinct. Moissanite: Basal, indistinct.

Composition

Cubic Zirconia: Zirconium Dioxide (ZrO2). Moissanite: Silicon Carbide (SiC).

Physical characteristics

• Crystal Habit: Typically encountered as cut and polished gemstones, not in natural crystal habit. Raw crystals are often blocky or tabular.
• Cleavage Type: Cubic Zirconia: Indistinct. Moissanite: Basal, indistinct.
• Fracture Type: Conchoidal.
• Tenacity: Brittle.
• Luster Type: Adamantine to sub-adamantine.

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