Mexican Fire Opal

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.

Fire Opal Brooch.jpg

Edwardian Faceted Fire Opal Brooch.
Photo courtesy of Sotheby's.

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


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.