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Diamond Simulant

Synthetic Mineral

Cubic Zirconia or Moissanite (likely synthetic)

Also known as: Cubic Zirconia (CZ), Moissanite (synthetic)

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Description

Diamond simulants are materials that visually resemble natural diamonds but possess different chemical compositions and physical properties. The two most common and successful diamond simulants are Cubic Zirconia (CZ) and synthetic Moissanite. Both are laboratory-grown materials, designed to mimic the brilliance, fire, and hardness of natural diamonds at a significantly lower cost. They are distinct from synthetic diamonds, which are actual diamonds grown in a lab.

How to Identify

Color
Typically colorless (D-F equivalent on diamond color scale), but can be produced in various colors.
Luster
Adamantine to sub-adamantine, often exhibiting a higher dispersion (fire) than natural diamond.
Texture
Smooth, faceted surfaces. No natural texture as they are cut and polished.
Crystal Form
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.
Cleavage
Cubic Zirconia: Indistinct. Moissanite: Basal, indistinct. Neither exhibits the perfect octahedral cleavage of diamond.
Geological Environment
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).

Quick Check

  • Color: Colorless (most common), but can be any color.
  • Luster: Adamantine to sub-adamantine.
  • Streak: White (as they are harder than the streak plate).

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.

Formation

Synthetically grown in laboratories through various high-temperature processes.

Usage

Primarily used as a diamond substitute in jewelry due to its similar appearance and optical properties.

Age Distribution

Modern (since 1970s for CZ, 1990s for synthetic Moissanite)

Where to Find

Laboratories and Manufacturing Facilities

Cubic Zirconia is produced globally, with major manufacturing centers in Russia, China, and Thailand. Synthetic Moissanite is primarily produced by Charles & Colvard in the United States, though other manufacturers exist.

Finding Tips

Distinguishing from Natural Diamond

Use a diamond tester (thermal or electrical conductivity). CZ is a thermal insulator, Moissanite is an electrical conductor (similar to diamond but different thermal properties). Observe fire/dispersion: Moissanite has significantly higher fire than diamond. Examine facet junctions: Moissanite often shows double refraction (facet doubling) under magnification, which diamond does not. Check specific gravity: CZ (5.6-6.0) is much denser than diamond (3.52); Moissanite (3.22) is slightly less dense than diamond.

Identifying CZ vs. Moissanite

Moissanite is harder (9.25 on Mohs) than CZ (8-8.5). Moissanite exhibits double refraction, which can be seen by looking through the crown facets at the pavilion facets. CZ is singly refractive. Moissanite often has needle-like inclusions visible under magnification, while CZ is typically flawless.

Similar Rocks

Natural Diamond

Carbon (C)

Also known as: Diamond

Synthetic Diamond

Carbon (C)

Also known as: Lab-grown Diamond

White Sapphire

Corundum (Al2O3)

Also known as: Colorless Sapphire

White Topaz

Al2SiO4(F,OH)2

Also known as: Colorless Topaz

Scientific Classification

Mineral Class
Oxide (Cubic Zirconia), Carbide (Moissanite)
Group
Synthetic materials, not naturally occurring minerals.
Crystal System
Cubic Zirconia: Isometric. Moissanite: Hexagonal.
Chemical Formula
Cubic Zirconia: ZrO2. Moissanite: SiC.
Composition
Cubic Zirconia: Zirconium dioxide. Moissanite: Silicon carbide.

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