Matrix opals are an opal type composed of precious opal distributed throughout its host rock. Some say Marvel’s Infinity War is the most ambitious crossover event in history; you won’t find matrix opals at the box office, but they present an equally stunning crossover of opal and rock!
What is a “matrix” in a gemstone, though?
Nearly all gemstones are formed within the earth, usually in the crevices of rocks. Most gems emerge attached to the rock they formed inside of, their host rock—but if the host rock penetrates the gem, it’s called a matrix.
What matrix is opal found in? Most opals form a matrix with ironstone, sandstone, or claystone, though some have basalt, limestone, quartzite, and rhyolite host rocks.
In this guide, you’ll learn the properties, meanings, and history behind matrix opals! First off, what basics should we know about matrix opal stones?
Matrix opal is a precious opal distributed throughout its host rock, creating a vein network, filling voids, or cementing spaces between the rock’s grains. The term “type 3 opal” also refers to matrix opal.
Precious opal is an opal that displays play-of-color, iridescent flashes of color throughout the stone. The precious opal in matrix opal has its usual composition: uniform stacks of equally sized, hydrated silica spheres.
On the Mohs scale of mineral hardness, matrix opal ranks 5.5-6.5, slightly higher than the usual 5.5-6 of other opals. This extra strength comes from the host rock. Color-wise, host rocks are usually black, brown, or dark gray.
What is the difference between matrix opal and boulder opal?
Above: Boulder matrix opal
Both varieties primarily from Australia, matrix opal and boulder opal both have precious opal mixed with its host rock. However, there are some key differences:
Mixture: Precious opal material appears as patches, seams, or veins in boulder opals. Precious opal in matrix opal forms vein networks, fills voids, or pervades between the rock’s grains.
Play-of-Color Distribution: Since precious opal is spread throughout matrix opal more evenly, these gems show more consistent color play throughout, rather than just localized areas like in boulder opal.
Vein Size: Boulder opal has larger precious opal veins, while matrix opal has a network of thin veins.
Despite their differences, the stones can also combine to form boulder matrix opal. Many gemologists define boulder opals by having ironstone—so, boulder matrix opals are matrix opals with an ironstone host rock. You’ll find this variety in Australia’s Yowah fields.
Outside of Australia, where does matrix opal come from? Let’s take a trip through the world’s suppliers.
You’ll find matrix opals primarily from Mexico, Honduras, and of course, Australia.
Mexican matrix opal is Cantera opal, a Mexican fire opal without play-of-color, or precious opal that merges with pinkish-tan rhyolite host rocks. The opal material is often transparent and may be categorized as jelly opal.
This opal is somewhat debated as a “real” matrix opal, as its characteristics are closer to boulder opals, but many sellers still classify it as matrix opal.
Honduras matrix opal usually has an opaque, dark basalt matrix speckled with precious opal throughout. The result is a glittering display of color similar to aventurescence.
Another rarer Honduran matrix opal variety is a seam opal comprising white opal and dark matrix layers crossed by parallel precious opal strips. The precious opal often creates a pinfire pattern. In both Honduran varieties, dark basalt is perfect for displaying bright color flashes.
As with most opals, Australia is the number one source for matrix opals. In fact, Australia is known for a specific type called Andamooka matrix opal.
What is Andamooka matrix opal?
Andamooka matrix opal comes from—you guessed it—Andamooka, a South Australia town. Also called “kopi” by local miners, this matrix opal is a fine-grained matrix rock with precious opal grains replacing pale limestone in small patches.
Another Andamooka variety is the rainbow opal matrix, composed of quartzite with precious opal deposited throughout quartzite’s grains. Queensland, Australia, produces matrix opals called yowah nuts, rounded sandstones cracked open to reveal layers of matrix opal inside.
Both Andamooka matrix opal varieties and many Honduran ones have porous host rocks, though rainbow opal matrix is more porous than Andamooka matrix opal. This absorbent quality makes it easier to treat, a property we’ll discuss next!
As you know, matrix opal rough can form with different host rocks. Certain rocks also create different conditions for matrix opal formation.
For instance, limestone matrix opals can form when opal fills small voids or replaces the soluble limestone after groundwater dissolves some of it. Sandstone, however, is porous, so silica settles between grains to cement the rock together.
Initially, a raw matrix opal may look worthless to miners—but all it takes is a skilled lapidarist to bring out the magic hidden inside.
The lapidarist figures out how to distribute the precious opal and decides the best orientation for displaying its play-of-color. The end result is often a cabochon with a unique, bright face.
Above: Treated matrix opal
After the gem is cut, it may receive treatments to enhance its appearance. Why? Matrix opals are often light-colored. Dark backgrounds on opals are rare and pricey, so treating lighter stones presents a more affordable alternative. Most matrix opals are also porous, making treatment a breeze.
Most treated stones start as untreated Andamooka matrix opal or Honduras matrix opal. There are two common treatments that both darken the body tone:
Smoking: Smoked opals are wrapped in paper, put in a closed container to heat, then let cool and washed. The soot permeates the porous material, darkening the background to enhance color play.
Sugar Treatment: Producing a similar result, sugar treatment involves soaking the stone in sugar water, then soaking it in sulphuric acid to carbonize the sugar and create a coat of dark specks.
Sellers should always identify treatments, usually by marking them as “treated matrix opal.”
Jewelers have practiced sugar treatments on Andamooka matrix opals for roughly 40 years, and that’s just a slice of this stone’s history!
Starting with its name, the word “matrix” comes from the Latin mater, meaning “mother,” though archaically, its translation was “uterus.” Ancient Romans used the word “matrix” for female animals or plants used as parents for breeding.
Today, "matrix" has a few definitions, including “something shaped like a pattern of lines and spaces.” Matrix opals incorporate both meanings, as a geological “womb” for new stones and the resulting opal patterns.
Historians posit that the first discovery of matrix opals occurred with the discovery of Australia’s Andamooka opal fields in 1930. There’s some debate over who made this find, but a detailed letter published in Australian Gems and Crafts Magazine in 1977 claims that well-sinkers Roy Shepherd and Sam Brookes found the first precious opal. They showed it to manager Mr. Foulis, who covertly investigated for more opals until 1933 when news about the opal field spread.
The world’s current largest matrix opal, found in Southern Australia, weighs 55,000 carats and has an estimated (uncut) value of over $1 million!
However, reports show dozens of opal deposits in Honduras were mined before Australia began its commercial mining.
Regardless of the first location, Andamooka opal captivated miners and royalty alike. Known as “The Queen’s Opal,” a 203-ct Andamooka matrix opal was set in a choker and gifted to Queen Elizabeth II in 1954 on her first trip to Australia.
Beyond royal connotations, what does matrix opal mean now?
Like all healing gemstones, matrix opal is a gift from Earth that you can use to appreciate your earthly existence while connecting to your spiritual side.
What are the spiritual properties of opal?
All opals symbolize innocence, hope, and love. Rumors have spread about opals bringing bad luck, but opals are actually incredibly lucky and optimistic. Some say matrix opal is the luckiest, most encouraging opal variety.
Culturally, certain elements of matrix opal characteristics contribute metaphysical meanings. Native Americans harnessed the Earth energy of ironstone, the Water energy of hydrated silica, and the Fire energy of its creation in medicine wheel rituals to contact spirit guides.
Matrix opal symbolizes new growth, creative freedom, and compassion. The combination of spontaneity and love in the stone’s spiritual properties make it a seductive stone, purportedly attracting desire to its wearer.
That said, how can you use matrix opal metaphysical properties?
Like its meanings, matrix opal properties for healing are abundant. Generally, the stone intensifies experiences, supports emotional balance, and brings mental clarity so you can clearly see your dreams and pursue them.
Physically, matrix opal helps heal fevers, cleanses the blood, and supports mothers by alleviating childbirth pain and empty-nest syndrome.
Emotionally, the stone can uncover deep, hidden emotions or truths and help you accept them. By providing comfort and resolving despair, you can use matrix opal to face your fears, improve your weaknesses, and recognize your potential.
On the spiritual side, matrix opal’s porous and mirror-like surfaces can allow you to absorb celestial energies and adopt a more reflective perspective. Said to protect while connecting you to cosmic consciousness, the stone is popular for shamanic work, foresight, and manifestation.
The protective properties tie to chakra work, as matrix opal opens the root chakra. This chakra is the center of grounding, stability, and perseverance. When it’s blocked, you may feel frustrated or on fearful high-alert to danger. Once matrix opal opens the chakra, you can feel safe, centered, and strong.
Now that you know the unique matrix opal properties, we wouldn’t blame you for feeling awestruck. Just know: “All we’re offering is the truth. Nothing more.” A little dramatic, but we had to throw in a Matrix reference!
If you’re looking for a one-of-a-kind opal that will turn heads and awaken your spirit, matrix opals are the way to go.
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