How to identify Opalite

To correctly identify Opalite (Synthetic Opal (often glass or resin)), 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 milky blue, bluish-white, or clear with an internal orange/pinkish glow when backlit. The color can shift depending on the background (blue against dark, milky white/orange against light).

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Vitreous (glassy) to resinous.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Smooth, often polished. May show conchoidal fracture surfaces if broken.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Amorphous (no crystal form), typically molded or cut into various shapes.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   None (due to amorphous nature).

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Not found in geological environments; it is manufactured in industrial settings.

Key Facts

Hardness

Glass Opalite: 5.5-6 on Mohs scale; Resin Opalite: 2-4 on Mohs scale.

Specific Gravity

Glass Opalite: 2.65-2.70; Resin Opalite: 1.08-1.18 (varies by composition).

Crystal System

Amorphous (no crystal system).

Color

Milky blue, bluish-white, clear with internal orange/pink glow.

Luster

Vitreous to resinous.

Transparency

Translucent to transparent.

Fracture

Conchoidal.

Cleavage

None.

Composition

Glass Opalite: Primarily silica (SiO2) with other additives (e.g., cryolite, metal oxides). Resin Opalite: Various synthetic polymers.

Physical characteristics

• Crystal Habit: None (amorphous).
• Cleavage Type: None.
• Fracture Type: Conchoidal.
• Tenacity: Brittle (glass) to somewhat flexible (resin).
• Luster Type: Vitreous (glassy) to resinous.

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