Synthetic opals have been produced and used in jewelry for more than three decades, and various imitation opals have been introduced in the trade. This article describes a new type of synthetic fire opal marketed as “Mexifire.” Some of the gemological properties of this synthetic are similar to those of natural fire opal. However, a low SG value (1.77) offers strong evidence of synthetic origin, and further indications are provided by a relatively low RI value (<1.40) and the presence of scattered pinpoints when examined with magnification.
Synthetic opals have been produced and used in jewelry for more than three decades, and various imitation opals have been introduced in the trade. This article describes a new type of synthetic fire opal marketed as “Mexifire.” Some of the gemological properties of this synthetic are similar to those of natural fire opal. However, a low SG value (1.77) offers strong evidence of synthetic origin, and further indications are provided by a relatively low RI value (<1.40) and the presence of scattered pinpoints when examined with magnification.
