How to identify Cubic Zirconia

To correctly identify Cubic Zirconia (Cubic Zirconia (likely)), 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-E-F equivalent on diamond color scale), but can be synthesized in various colors (e.g., yellow, pink, blue, green, black) by adding dopants.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Adamantine to sub-adamantine, often appearing slightly more 'glassy' than diamond.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Smooth, hard, and dense.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Cubic system, typically grown as single crystals and then cut and polished into various gemstone shapes.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   None (or very poor/indistinct). CZ exhibits conchoidal fracture.

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Not found in natural geological environments; exclusively a synthetic material produced in laboratories.

Key Facts

Hardness

8.0-8.5 on the Mohs scale (significantly lower than diamond's 10).

Specific Gravity

5.6-6.0 g/cm³ (much higher than diamond's 3.52 g/cm³). This difference is often noticeable by weight for similar-sized stones.

Crystal System

Cubic (isometric).

Color

Colorless, but can be produced in a wide range of colors.

Luster

Adamantine to sub-adamantine.

Transparency

Transparent to translucent.

Fracture

Conchoidal.

Cleavage

None.

Composition

Zirconium dioxide (ZrO2), typically stabilized with yttrium oxide (Y2O3) or calcium oxide (CaO).

Physical characteristics

• Crystal Habit: Typically grown as single crystals, then cut and polished into faceted gemstones. Does not form natural crystal habits.
• Cleavage Type: None. Exhibits conchoidal fracture.
• Fracture Type: Conchoidal, similar to glass.
• Tenacity: Brittle.
• Luster Type: Adamantine to sub-adamantine.

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