Mexico is of course, the main source of the Mexican fire opal. Very highly prized Mexican fire opals are excavated in open-cast mines in Queretaro, Mexico. However, the stone can also be found in Guatemala, Honduras, the United States, and Australia, where more precious varieties are known to be found. Germany has been importing most of Mexico's best fire opals for many decades now.
Many people mistakenly think that a fire opal is simply an opal with a lot of red showing in its beautiful, iridescent display of colors. This is an understandable mistake as the word "fire" usually refers to this beautiful iridescent display of colors opals possess, not the opal's actual body color. A Mexican fire opal is actually very different than the opal we are used to seeing. While an opal is opaque and white, displaying an iridescent play of colors in every color of the rainbow, the Mexican fire opal is transparent to translucent, with a uniform red, orange, yellow, or brownish body color. Fire opals can come either with or without a play of color or fire. Iron content is what gives Mexican fire opals their orange color. The best, most highly prized specimen are transparent, have a play of color within the stone, and are of a fire-red orange color. These specimens can demand a retail price of up to $300 per carat. In contrast, translucent stones that are brownish or yellowish, sell for $5 a carat. Fire opals are usually faceted, and the wearer of the gem must be aware of the fragility of the stone. Like all opals, Mexican fire opals can crack in the course of time if it is not properly taken care of.
The Mexican fire opal has many positive attributes to bring to the life of its wearer. Physically, it is said to have the power to heal the lower back, kidneys, and can stimulate sexual organs. Mentally, the fire opal is said to be a wonderful stone for those people who are shy and lack self-confidence. Its fire supposedly rouses them and gives them the boost of self-confidence they need. The fire opal is also said to be able to help those who have just suffered from abusive relationships. As the stone is said to be able to heal and relieve memories of rape, incest and sexual abuse, it also encourages positive and healthy sexuality and relationships. Fire opal symbolizes joy of the heart. It has also been said to be used to attract money. Placing a fire opal in your place of business is a good way to attract customers.
Mexican fire opals are named for their uniform flaming orange or cherry red body color. They are always very brightly colored, and can be a little bit cloudy to almost perfectly transparent. Transparent specimens have a good luster. Like the traditional opal, fire opals can occasionally display signs of iridescence in very bright light. Fire opals have a very low density, lower than that of glass, with which it is sometimes confused. Fire opals, like other opals, are relatively hard, rating a 5.5 to 6.5 on the hardness scale.
Fire opals are extremely fragile, and suffer from changes in humidity, temperature, and even light. However, with the proper care, your fire opal can last a long time. Opals contain as much as 20% water, which means they can get very dry and wind up cracking. This phenomenon is called "Crazing," and may be avoided by soaking your opal in water for a few hours, occasionally. Some opals are actually filled with oil, wax, or plastic, to avoid crazing. It is important that opals never be touched with any oils or chemicals. It is also important to protect your stone from any blows or scratches.