The opal gemstones found throughout the world are known for their beautiful hues and glints of color. There is an important distinction between the uniformly colored fire opal and the flashing colors of fiery opal. Understanding the difference is important when shopping for your an opal gemstone, so you can purchase the right stone for you.
Fire Opal Color
Fire opal has a red, orange or yellowish color. Unlike the name fiery opal, the name fire opal does not refer to flashes of color. Fire opal has a uniform color, a trait called non-opalescence. The background color of opal comes from small traces of iron oxide.
Fiery Opal Color
The term “fiery” in the name of this gemstone refers to the flashes of fire, or color play, you can see in it. This type of opal is also called precious opal. Fiery opal has sparks of color on a main background color, usually light blue or white. You will find fiery opals with flecks of red, orange, blue, green and/or purple. Black opals are hard to find and are expensive; they have a darker gray or bluish-black background color, which may have red or orange worked into it. As with the fire opal, the background color is caused by iron oxide present when the gemstone was formed.
Opal is comprised mostly of silicon dioxide and various amounts of water. The water percentage indicates the temperature of the rock in which the opal formed, so it varies for both kinds of opal. This gemstone doesn’t form like other crystals. Opal is the only gemstone mineral that is amorphous and without the regular internal atomic structure that makes up other crystals. The opal minerals seep through the cracks of other rocks and forms there. Because of their form, opals are cut into facets or cabochons, often in an oval shape.
The majority of opals originate in Mexico and are cut into faceted stones. They are also found in Australia, Guatemala, Canada, the United States, Brazil and Ethiopia.
References and Resources"Rocks and Minerals"; Michael O'Donoghue; 1991.
International Colored Gemstone Association: Fire Opal
Stellar Jewelry: Fire Opal
The Image: Opal