Where is Opalite found?

Opalite occurs in specific geological environments. Knowing where to look, and in what kind of rock, is the difference between going home empty-handed and finding a great specimen.

Where to find Opalite

Collecting tips

1. Check for Bubbles. Examine the material closely for small, spherical gas bubbles, which are characteristic of glass and not found in natural opal or moonstone.
2. Observe Optical Effects. Note the distinct blue glow against dark backgrounds and orange/yellow glow when backlit. Natural opal exhibits a 'play-of-color' (diffraction of light into spectral colors), while moonstone shows adularescence (a schiller or billowy light effect) that is typically silvery-white to bluish, not the distinct blue/orange shift of Opalite glass.
3. Hardness Test (with caution). Opalite glass typically has a Mohs hardness of 5.5-6. This can help distinguish it from natural opal (5.5-6.5) and moonstone (6-6.5), though this test is not definitive and can damage the material.
4. Specific Gravity. Opalite glass generally has a specific gravity around 2.65-2.80, which can be higher than natural opal (1.98-2.25) and similar to moonstone (2.56-2.59). This requires specialized equipment.

Quick Check

Color:

Milky white to pale blue with internal orange/yellow glow when backlit.

Luster:

Vitreous (glassy).

Streak:

White (as it is glass, it will not produce a streak on a streak plate).

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