Fire opal refers to the variety of transparent red, orange or orangy-red opal usually lacking play-of-color. Fire opal is cut en cabochon as well as faceted. The source for this gem material is Mexico, hence the name.

Gemological Information

Gemological Information for Mexican Fire Opal
Color	Red, Orange, Orangy-Red
Crystal Structure	Amorphous
Refractive Index	1.43-1.47
Durability	Relatively Poor
Hardness	5.5-6
Similar stones	Opal can be confused with glasses and some plastics. Redish-brown Chalcedony for its color.
Treatments	Fracture Filling, Synthetics.
Country of origin	Mexico, Brazil
Mexican Fire Opal Care
Ultrasonic cleaning	Never
Steam cleaning	Never
Warm soapy water	Safe
Chemical attack	Avoid
Light sensitivity	Stable
Heat sensitivity	May crack

Sources

Gem Reference Guide, Los Angeles: Gemological Institute of America, 1988. Pp. 164-167.

Newman, Harold. An Illustrated Dictionary of Jewelry, New York: Thames and Hudson, 1981. Pp. 126.

Schumann, Walter. Gemstones of the World, New York: Sterling Publishing, Co., 1977. Pp. 152.