Fire opal is a variety of opal gemstones that come in red, orange and yellow colours. Being known for their vivid body colour, fire opals are often referred to as Mexican opals since many fire opals are found in Mexico and resemble beautiful Mexican sunset.
Fire Opal Origin and Sources
Fire opal is the variety of opal gemstone. The name “fire opal” comes from its fiery orange colour, though it can also be found in red, yellow, brown and even white colours.
Fire opals are mainly associated with Mexico and are mined in the Mexican states Hidalgo, Queretaro, San Luis Potosi, Chihuahua, Michoacan, and Julisio.
The most important mines were discovered in 1835 in Queretaro and are still producing today.
Some opals from Mexico exhibit bluish and golden internal sheen and are referred to as Mexican water opals or hydrophanous opals rather than Mexican fire opals.
Other fire opal mines were discovered in USA, Australia, Canada, British Columbia Guatemala and Northeast Brazil.
Fire Opal Colour
The colour range of fire opals is quite wide, and some pieces display several colours in a single stone. They look exceptionally beautiful when viewed in daylight after sunrise or just before sunset.
Fire opals come from yellow to vivid orange and from red to brown. The best stones exhibit a fiery red-orange colour combination.
Darker varieties typically show more play of colour than yellow (golden) coloured ones. Fire opals that do not exhibit any play of colour may be referred to as jelly opals.
The golden yellow gems are highly regarded, but the most sought-after fire opal colours are saturated orange and orange-red.
For example, stones with a saturated orange colour are more expensive than those with a pale orange hue. Besides, the gems that have higher brilliance are always more valuable than gems with duller hues.
As a general rule, the more intense the hue of an opal, the more valuable it is.
Fire Opal Clarity
Unlike other opal varieties, good quality fire opals can be translucent to transparent.
The stones that have fewer internal flaws look clean and are more valuable than included gems that tend to have a cloudy appearance.
Perfectly clean fire opals are rare. It’s natural for a stone to have some inclusions, but you should avoid gems that have cracks as these flaws can put the integrity of the gem at risk.
It’s best to choose the stones that look clean to the naked eye and whose tone is as even as possible.
Fire Opal Cut and Shape
Since fire opals can be transparent to translucent, you can often find higher-grade gems to be faceted instead of being cut into a cabochon shape. The most popular fire opal shapes are traditional ovals, rounds, cushions and pears.
Darker varieties such as brown fire opals are cut into cabochon to maximize the play of colour.
In case you are considering a faceted stone, keep in mind that opal is a relatively soft gemstone (5.5 to 6.5 on the Mohs scale) and the edges of its facets will become less shape with time depending on how often you wear the gem.
Fire Opal Care and Cleaning
Opals including fire opals are delicate gemstones since they have a high level of water content. In fact, the water content can make up to 21% of their weight.
This is the reason why opals are vulnerable to dehydration and temperature fluctuations, meaning if an opal is allowed to dry, it will crack and even fade.
It is very important to properly store your gemstone to protect it from drying out. It is recommended to place a moist cloth inside a sealed plastic bag along with the fire opal.
Since fire opals are relatively soft gemstones, they are prone to scratching. Simply wiping the dust off the opal will gradually reduce its original polish. That is why it is recommended to rinse fire opals under warm water and dry with a soft cloth.
Needless to say, you should never use bleach and other chemicals or put your gemstone into an ultrasonic cleaner since the vibrations will cause an opal to crack.
