Mexican fire opals are red, orange, or yellow varieties of the mineraloid opal, a hydrated silica stone. Though fire opals can come from outside Mexico, fire opals from Mexico are renowned for their vibrant coloring, unique transparency, and origins in Mexican history. In fact, fire opals are considered the national gemstone of Mexico.

Like other opals, Mexican fire opals can be either precious or common (with or without play-of-color, respectively). The iridescent color-play of precious fire opals comes from their internal structure, but the autumnal body colors of all fire opals come from traces of iron.

Fire opals are October birthstones. They symbolize burning love, joy, and passion. Ancient Mayans and Aztecs called the gems quetzalitzlipyollitli, meaning “stone of the bird of paradise.”

FAQs

Are there different types of Mexican fire opals?

Yep! Besides precious and common fire opals, other varieties include:

> Matrix Fire Opals — Intricately dispersed through the host rock they grew inside
> Cantera Opal — Formed as matrix in rhyolite, found in Mexican quarries (canteras), and cut into egg shapes
> Contraluz Fire Opal — Precious fire opal with play-of-color appearing to float inside when lit from behind “against light” (contraluz)

What makes fire opals unique?

Fire opals are unique from other types of opal in being commonly translucent to transparent rather than opaque, more often faceted than cut as cabochons, more vibrant in color, and forming in volcanoes.

How are Mexican fire opals formed?

Unlike other opals that form from silica-infused water at low temperatures in the Earth’s crust, fire opals form from silica-infused water that settles in crevices of very hot lava within ancient volcanoes. From there, the water evaporates and the hydrated silica solidifies into fire opal.

Where are Mexican fire opals typically mined?

The most important source in Mexico is Querétaro, followed by Hidalgo and Jalisco. Four other states in Mexico also produce fire opal.

Are fire opals rare?

Somewhat. Fire opals are rarer than other types of opal — though not the rarest opal variety and not as rare as other gemstones. The rarest kind of fire opals are transparent with a pure, vibrant red body color and strong play-of-color.

What colors are common in Mexican fire opals?

Most Mexican fire opals are orange, but colors also include shades of yellow, brown, and red, with bright, pure red fire opals being the most sought-after.

What is the difference between Mexican fire opals and other fire opals?

Mexico is the first and most abundant source of fire opals. They’re known for their more vibrant coloring, but most of them are common opals. Other sources produce fire opals with distinct traits, like the neon green and violet color flashes of precious Ethiopian fire opals or the massive sizes of Dourado fire opals from Brazil.

Additionally, some call any precious opal “fire opal” — even if it doesn’t have a red, orange, or yellow body color — if it has a fiery play-of-color.

What factors influence the value of Mexican fire opals?

The main grading factors are:

> Color: Uniform, bright red or orange-red fire opal body colors are most sought-after. Yellows and oranges are more common, while uneven body color distribution lowers value.
> Iridescence: Play-of-color is rare in fire opals from Mexico, making strong color-play a value booster.
> Transparency & Clarity: Higher degrees of transparency and clarity (meaning fewer visible inclusions) increase the value and durability of fire opals.
> Carat Weight: Fire opals in larger sizes, especially with fewer flaws, are more rare and valuable.

The stone’s cut, treatments, and origin (natural vs synthetic) also matter. Faceted cuts are best. High clarity and transparency also increase value. Smoke or sugar treatments for color-enhancing lower value. Synthetic (lab-created) fire opals are less valuable than natural ones.

How can I identify a genuine Mexican fire opal?

Synthetic fire opals called Mexifire® first entered the market in 2008. The early Mexifire® fire opals have lower density (1.63 vs 1.92-2.38) and different inclusions (scattered pinpoints vs dendrite or flaky patterns) than natural fire opals. Newer Mexifire® opals still have pinpoint inclusions but a higher density closer to natural fire opals.

Mexican fire opal simulants — often made of plastic or resin — are usually lower in density, more opaque, and sometimes bubbles on their surface. Natural fire opals also have a signature greenish to greenish-brown fluorescence.

Can fire opals be used in jewelry?

Absolutely. In fact, Mexican fire opal jewelry dates back to the ancient Aztecs. High-quality fire opals are especially suited to earrings, which allow their brilliance to sparkle at every turn. But fire opals can be used in any jewelry — just use protective settings for more vulnerable jewelry like fire opal rings.

How should I care for a Mexican fire opal?

Opt for protective mountings on faceted fire opal jewelry like rings or bracelets and remove the jewelry before sleep or vigorous activities. Only clean the stones with mild soap, warm water, and a soft brush.

Keep these gems away from exposure to intense light, extreme heat, rapid temperature changes, and strong chemicals. Store your Mexican fire opal with a moist cotton ball or cloth to avoid drying, and keep both in a dark, pH-neutral place away from harder gems.

What is the process for purchasing Mexican fire opals from your site?

Start by creating an account to track orders and talk to sellers. Then, browse the hundreds of fire opals available, with options in various cuts, styles, and price points. You can buy Catalogue or Buy it Now fire opals right away — just look for a green price with a cart symbol.

Want to dive into auctions? Make a bid on an open reserve or no-reserve fire opal auction with minimum bids starting at just $1. Set your maximum bid and let our system do the work outbidding others for you up to your set maximum.

Our Mexican fire opals are all offered by reputable sellers that have been thoroughly vetted through our strict Verified Sellers program. If you’re unsure about any fire opal listing, use our free Opal Sheriff program to get an audit by a third-party expert gemologist.

参考文献