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Opal FAQs – What You Need to Know Before Buying

opal gemstone frequently asked questions

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Arguably the most diverse, unique and beautiful of all birthstones, opal is a special gemstone used for various purposes as well as in jewelry. In this article, we’ve covered 15 frequently asked questions about opal gemstones, so that you’ll be well informed when buying yours. Let’s go ahead and take a look.

What are opal gemstones?

Ethiopian fire opal

Natural Ethiopian Fire Opal. See it here.

Opals are naturally occuring substances similar to minerals which posses an amorphous character, meaning that they lack a specific shape.  They’re composed of hydrated silica spheres which are so tiny, they cannot be seen by the naked eye.

These gorgeous gemstones are formed when silica-rich water flows into deep fissures in rocks such as sandstone, marl, rhyolite and basalt. The formation process is an extremely long one, taking 5-6 million years to form just one centimeter of opal.

There are two classes of opal – common and precious. The main difference between these two types is that precious opals are iridescent (meaning they show luminous colors that appear to change when viewed from different angles) whereas common opals are not.

What color are opal gemstones?

Natural black opal pendant

Natural black opal pendant. See it here.

The color and characteristics of opals depend on the conditions in which these stones are formed. They can be translucent, opaque or transparent with almost any specific background color of the visual spectrum including white and black. Black opals are considered to be the rarest of all opals whereas gray, white and green are some of the most common colors found in the market.

Where are opals found?

While opals are found all around the world, Australia is known for producing 95% of the precious opal for use in the jewelry industry. First mined in Queensland in 1875, opal became the official national gemstone of the country in 1993. The climate conditions in Australia are ideal for the formation of these beautiful stones which is why some of the best opals in the world are formed there. Opals are also commonly found in many other countries including Ethiopia, Mexico, Brazil, Czech, Indonesia and the U.S.

What are the types of opal?

There are several types of opals which belong to the two categories ‘precious’ and ‘common’. Precious opals are typically used for jewelry making whereas common opals are too soft for jewelry, so they’re used for other purposes. Let’s take a closer look at these two types of gemstones, starting with precious opals:

  • Black opals – The rarest and most highly valued type of opal. These display all the colors of the rainbow against a dark body tone which makes the colors stand out, giving them a rich look.
  • White opals – These have a light body tone and are also known as ‘milky opal’ or ‘white opal’. Precious light opals typically have a soft and beautiful pastel-like quality to them.
  • Crystal opals – This type of opal is translucent, meaning that when illuminated, some amount of light passes through it. Although it’s called ‘crystal opal’, it’s structure isn’t crystalline at all. It was named so because of its translucency which looks similar to crystalline materials like glass.
  • Boulder opals – This is an opal that’s attached to its host rock, typically sandstone or ironstone, a brownish rock, rich in iron. The best boulder opals in the world come from Western Queensland, Australia where it’s formed mostly in ironstone. 

Common opals, also known as ‘potch’ are opals that don’t exhibit any iridescence or ‘play-of-color’ that’s seen in the precious stones. Potch is made exactly from the same mineral as other opals. However, the tiny silica spheres in potch are all mixed up, unlike in precious opals in which they’re evenly laid out and neatly stacked.

What are opals used for?

Emerald opal earrings

Stunning emerald opal earrings. See them here.

While precious opals are primarily used in jewelry, common opals are mined for use as fillers, abrasives and insulation media. They’re also one of the ingredients used in making ceramics. However, only about 5% of all opals that are mined are used for such purposes since the other 95% is used for making ornaments and jewelry. They are also an important part of gemstone therapy.

How can I clean my opal?

Like most other gemstones, solid opals can be cleaned with warm water, mild detergent and a soft cloth or toothbrush. Only brush it if absolutely necessary, otherwise try to avoid doing so as much as possible since it can leave tiny scratches on the stone’s surface. While these scratches usually won’t be seen by the naked eye, they can make the stone look dull and lose its shine as they accumulate over time.

Never use harsh chemicals like bleach, chlorine or strong detergents on your stone since they can damage it. To clean doublets and triplets, wiping with a soft, damp cloth and mild soap or detergent should be enough. Keep in mind that doublets and triplets should never be immersed in water since the water will penetrate the stone and cause damage. Opals should never be cleaned in ultrasonic cleaners since the vibrations can cause the stone to crack.

If your opal loses its shiny appearance due to miniscule scuff marks and scratches, take it to an opal cutter who will polish it, making it look as good as new again.

Is opal good luck?

Hamsa opal pendant

Hamsa opal pendant, a good luck charm. See it here.

During the Middle Ages, opals came to be associated with good luck. The Romans believed that the opal was one of the luckiest gems and regarded it as a symbol of hope. Although the stone was strongly associated with good fortune, there are numerous legends and tales that link it with the evil eye, bad luck and death.

In the latter half of the 19th century, Spanish King Alfonzo gifted an opal ring to his wife who died shortly after receiving it. The ring was then passed on to other members of his family and each one who received it died within a short period of time. It finally returned to Alfonzo who decided to wear it but soon, he too, passed away like the rest of his family members.

While it’s likely that these deaths could have occurred due to old age, diseases such as typhoid fever or the Cholera epidemic that was plaguing the country, the link between opals and death grew stronger. Today, opal is the October birthstone and is said to bring bad luck to anyone who wears it unless its their birthstone.

How can you tell a real opal from a fake?

‘Fake’ opals aren’t actually fake since they have the same properties of real opals. In fact, they’re made of real opal mixed with other chemically different materials. Many of the opals sold on the market today are synthetic imitations and it’s important to know the difference between these and the real thing so you’ll know what you’re paying for.

Synthetic opals are less dense than real opals which makes them lighter and when looked at under a magnifying glass, you can see a regular pattern of color. Natural stones, on the other hand don’t exhibit this regularity in their color and tone.

Another way to spot a synthetic opal is to light it with UV light. You’ll notice that the stone doesn’t glow or shine brightly like a genuine opal would.

Do opals have healing properties?

Natural opal necklace

Natural opal healing crystal necklace. See it here.

Opals are believed to possess extraordinary healing properties while bringing exuberance and joy to one’s life. It’s considered an emotional stone that reflects the mood of anyone who wears it, intensifying their emotions. Many believe that this magical gemstone has the power to treat diseases as well as fevers and infections and purify the blood. Some believe that opal can regulate insulin and even ease the pain of childbirth.

Which opal is the most valuable?

Semiprecious black opals

Ethiopian black opals. See them here.

The most valuable and highly prized type of opals are the ones with a dark or black body tone, known as ‘black opals’. The reason they’re so valuable is because their dark tone displays more vibrant colors than opals with lighter body tones. Black opals can be found in a wide range of prices from $50 a carat to $10,000, depending on their quality.

What does black opal symbolize?

As we’ve mention before, black opal is a rare and valuable gemstone that’s also famous as the stone of prediction. It shows off a unique spectrum of colors which is why it’s symbolic of harmony. Many people believe that black opals gave the wearer the power to see the future and bring good fortune. In the past, people regarded black opals as symbols of hope or miracles and back in the ancient times this unique stone was believed to have a beautiful goddess inside it which gave it its magical, one-of-a-kind look.

How do I take care of my opal?

Opals are fairly soft gemstones, ranking at 5-6 on Mohs scale which means they’re about as hard as glass. While it won’t crack at the drop of a hat, the stone can get easily damaged so you’ll need to take excellent care of it. Taking good care of your opal will ensure that it lasts a lifetime.

Many believe that solid opals get easily damaged by water but this isn’t the case. In fact, most solid opals contain around 5-6% water which is why they can crack when there are rapid changes in the temperature or when placed in very dry conditions. Therefore, it’s important to avoid exposing your opal to very high temperatures like boiling water or extremely low humidity.

Opal doublets and triplets, unlike solid opals, should not be exposed to water too much since the water will infiltrate the layers of the stone, causing them to lift. When this happens, the doublet or triple will have a greyish, foggy appearance. However, this only happens with prolonged exposure to water so there’s no need to worry if you forget and wear it once or twice while showering .

How do I choose an opal gemstone?

When choosing an opal, make sure you assess the quality of the gemstone, taking its body tone, brilliance and color into considerations. Check to see if it has any imperfections like cracks or inclusions. Natural inclusions are fine but if you can see cracks in the stone, don’t buy it.

If you’re on a tight budget, you might want to consider a doublet or triplet since these are far cheaper than solid opals.

What are opal doublets and triplets?

Natural opal doublet ring

Australian boulder opal doublet ring. See it here.

Opal doublets and triplets are created by combining solid opal with a synthetic material to enhance the color of the stone and add thickness or strength to it. Opal doublets are pieces of solid opal glued to a dark backing that makes it look like solid black opal. Doublets aren’t worth as much as solid opals but they’re a great choice if you’re looking for a cost effective version of the real thing.

Opal triplet pendant

Silver opal triplet pendant. See it here.

Like doublets, opal triplets are created by sticking very thin slices of opal to a dark backing, but they have a domed top that’s made of clear quartz or glass. The dome protects the slices of solid opal but greatly decreases the value of these stones in comparison to doublets.

Are opals rare?

While silica is one of the most commonly found minerals on Earth, precious opals are extremely rare: even more than diamonds. This is because the natural formation process is one that rarely occurs. Most opals that are mined are common ones without gemstone colors, known as ‘potch’ as we’ve mentioned earlier.  

Potch is commonly found in grey, white, amber or black colors. Sometimes, miners come across opals that display gemstone colors, but most of the time these stones are difficult to cut or facet since they’re either too sandy or thin to handle. These types of opals that can’t be used for jewelry, are used for other purposes.

Wrapping Up

Opals are beautiful stones that make stunning jewelry pieces. The special thing about these gemstones is that each one is unique and no two are ever alike. While some opals can be very expensive, there are many options available out there to choose from according to your budget. Not only are these lovely gemstones a wonderful addition to your jewelry or gemstone collection, but they’re are also an excellent gift choice for anyone.