Exploring Opal and Tourmaline Birthstone

September 16, 2021
Birthstones , Gemstones

Birthstones for October: The Rainbow of Color Options of Opal and Tourmaline

Birthstones are stunning gems that connect a person with the time of year they were born. They’re also often rumored to carry specific properties, but even without that, birthstones make stunning jewelry and interesting conversation pieces. So, what is the birthstone for October? We’ll discuss that and more in this article.

What Is the Birthstone for October?

Each month of the year has a specific birthstone associated with it. However, those born in October have two: opal and tourmaline.

What Is Opal?

Opal and Tourmaline Birthstone

Opal is a rare gemstone primarily mined in Australia, although it can be found in other parts of the world. The name comes from the Greek word opallios, which means “a visible change in color”. When opals are viewed in light and turned gently, they seem to change colors and sparkle. This is also where we get the word opalescent.

That multicolored and color-changing nature meant that opals commanded considerable respect through the centuries. For instance, the Romans believed that opals were the most precious of all gemstones. However, they differ dramatically from other gemstones not just in their color, but also in their structure, chemical makeup, and how they are formed.

How Is Opal Formed?

Opals are not formed like other gemstones, which require carbon, inclusions, and pressure. Instead, opals are formed by rainwater and silica. When rain falls onto porous rock, it seeps down into the stone, taking minute bits of silica with it. In some instances, it can collect in gaps within the rock, where it undergoes sedimentation, similar to how sandstone and limestone are formed.

Technically, opal is a form of hydrated silica and water. Up to 20% of an opal’s mass is water trapped within the silica structure. Gem-quality opals usually contain 10% or less, though. And, because of the silica content, opals can be almost any color, from opalescent white stones to stunning black opals, orange opals, and fire opals.

Where Are Opals Mined?

Opals have been mined around the world for thousands of years. Some of the areas where these stones are found include Brazil, Mexico, Honduras, and even some western states in the US. With that being said, the lion’s share of opals today comes from one place: Australia.

Australia has three primary opal-producing regions – New South Wales, Queensland, and South Australia. Each of these areas brings something unique to the table. In addition to boasting the largest opal deposits, Australia also produces some of the finest stones in the world.

Below, you’ll find a quick rundown of what you can expect in terms of opals from the various mining regions around Australia. All of these areas surround the boundary of an ancient, shallow ocean, dubbed the Great Inland Sea, which dried up millions of years ago.

New South Wales

New South Wales is justly famed for its sheer volume of high-value opals. In fact, this region accounts for a significant percentage of Australia’s premium opal production. It is also the only place where black opals are mined (Lightning Ridge). White Cliffs is also famed for its production of white and crystal opals.


Queensland has many opal-producing areas, including Quilpie, Winton, Opalton, and Yowah. True to its name, Opalton is home to one of the largest worked opal deposits in the region. Many of the opals mined in Queensland are boulder opals, which are formed within ironstone, a type of sedimentary rock that dates back to the Cretaceous period.

South Australia

From Coober Pedy to Lambina, Mintabie to Andamooka, there are many opal-producing areas in South Australia. Many of them produce white opals, which is the region’s primary claim to fame. South Australia is the largest opal-producing region in Australia by volume.

How Much Is Opal Worth?

Opal’s value is determined by many different factors. Generally, lighter colored stones are less valuable, while darker stones are more valuable. This is because darker stones tend to show their colors better than lighter stones, so they command a higher price on the market. Size also plays a role in determining how much opal is worth. Other factors that play into opal’s value include brilliance, pattern, color bar thickness, color play, and faults in the stone. Rare, high-grade opals can be as costly as fine diamonds, particularly black opals, which are prized for their incredible beauty.

Types of Opal Jewelry

When it comes to opal jewelry, the sky is the limit. You’ll find this stunning stone makes scintillating pieces, whether you choose a black opal pendant, a multi-colored opal necklace, orange fire opal and diamond ring, a teardrop Ethiopian opal, and diamond pendant necklace, or something else altogether.

It’s also possible to find custom jewelry design online that includes high-quality opals and stunning settings. Custom rings and custom necklaces featuring opals allow you to make a statement and achieve a look that is uniquely yours.

What Is Tourmaline?

Our second October birthstone is tourmaline. Like opal, tourmaline also comes in an incredible range of colors and hues, so there are plenty of options to choose from. In fact, a single stone can contain multiple colors, including pink, yellow, brown, and black. Most colors and color combinations are used in jewelry today, although black is rarely used and is most associated with mourning jewelry.

Tourmaline has been mined around the world, but specific colors and color combinations usually come from particular places. For instance, deep emerald-green tourmaline was not discovered until the Spanish began exploring South America. The same is true for Paraiba, which is an intense blue or blue-green tourmaline only found in Brazil. Chrome tourmaline is found only in Brazil and Africa.

How Is Tourmaline Formed?

Tourmaline is formed much like other gemstones – through heat and pressure, deep in the earth. Its colors come from the inclusion of different minerals, often metals, during the stone’s formation. For instance, green and blue come from the inclusion of iron and possibly titanium. Red, pink, and yellow come from the inclusion of manganese. Radiation (both natural and artificial) can also cause colors to form or even to change.

Tourmaline can be a single color or multihued. For instance, rubellite is usually red, orange-red, or red-brown, while indicolite is blue, blue-green, or even blue-violet. Parti-colored tourmaline shows multiple colors – the green and pink of watermelon tourmaline is a good example, but there are other combinations possible. Watermelon tourmaline is green on the outside and pink in the middle, and this type is usually cut in slices to highlight that striking color difference.

How Much Is Tourmaline Worth?

You’ll need to consider many different factors when it comes to determining how much tourmaline is worth. Size and weight are two primary factors, but you must also consider rarity. For instance, Paraiba tourmalines can cost tens of thousands of dollars per carat. More common color combinations may cost as little as $50 per carat even with the same cut, color, and clarity.

However, unlike other gemstones, a high level of inclusions may not drive down the price the way they do with some diamonds. Instead, it can dramatically increase the price depending on the color those inclusions create. 

Types of Tourmaline Jewelry

Like opal, tourmaline can be used with a very wide range of jewelry. It can also be combined with other gemstones to create stunning color combinations that scintillate and mesmerize. For instance, a green tourmaline diamond ring or green tourmaline and diamond halo and split shank ring could be just the accouterment for the discerning woman who prefers classic elegance and beauty. On the other hand, a watermelon tourmaline and diamond halo ring or a watermelon tourmaline necklace with diamond accents offer a unique combination of colors and a very different cut for a woman who wants to stand out from the crowd.

As with opal jewelry, you’ll find that the right jeweler can offer custom jewelry design online. Whether you’re interested in custom rings featuring tourmaline or you want custom necklaces with tourmaline stone, it’s possible to bring your ideas to life.

It’s Time to Celebrate October Babies

From the color-changing properties of opals to the multi-hued nature of tourmaline, October babies have a wealth of options open to them when it comes to precious gemstone jewelry. Plus, with the incomparable range of colors and shades, there is something that will fit every personality and even specific events, from formal affairs like galas and weddings to everyday wear.

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