Opals of all varieties have been synthesized experimentally and commercially. The discovery of the ordered sphere structure of precious opal led to its synthesis by Pierre Gilson in 1974. The resulting material is distinguishable from natural opal by its regularity. Under magnification, the patches of color are visible in a lizard skin or also chicken wire pattern. Furthermore, synthetic opals do not fluoresce under ultraviolet light. Synthetics are also generally lower in density. And they are often highly porous.
Most synthetics, however, are more correctly termed imitation opal. They contain substances not found in natural opal. Such as plastic stabilizers. Imitation opals seen in vintage jewelry. They are often foiled glass. Also glass based slocum stone. Or later plastic materials.
Directional columnar pattern in Gilson imitation opal
Other research in microporous structures have yielded highly ordered materials. It have similar optical properties to opals. And have been used in cosmetics.
Slocum stone, sometimes sold as slocum opal is an early opal simulant. It was briefly popular prior to the introduction of synthetics. And less expensive simulants. It is a silicate glass which shows traces of sodium, also magnesium, aluminum and titanium. We can find it in several base colors. Very thin layers of metallic film make the artificial opalescence. Estimated at 30 nanometers in thickness, in the form of translucent flakes. It produces a thin film interference effect. These flakes themselves lend color, along with colorant within the glass base. Bubbles and also swirls typical of glass are other typical inclusions. We can see it under magnification. In later examples, built up laminations are visible when viewed from the side.
Opalite is a trade name for man-made opalized glass. And various opal simulants. Other names for this glass product include argenon, also sea opal, opal moonstone and other similar names. It is also used to promote impure varieties of variously colored common opal.