Happy Birthday, October! Your Birthstones Are Opal and Tourmaline

October babies are exceptionally lucky when it comes to birthstones. Instead of having just one gemstone to choose from, they can celebrate with two of the most colourful and individual gemstones in the world: opal and tourmaline.

October is also a particularly special month here at Alex Ruby Trading Co., because one of our founders, Allie, celebrates her birthday on 13 October.

Happy birthday, Allie—and happy birthday to all our fellow October babies!

Whether you prefer the shifting rainbow colours of opal or the extraordinary variety of tourmaline, October’s birthstones offer something for almost every taste.

So, let’s explore what makes these two remarkable gemstones so fascinating.

What Are the October Birthstones?

Two gemstones represent October:

• Opal, the traditional October birthstone
• Tourmaline, the more modern alternative

At first glance, these gemstones look very different. Opal produces flashes of spectral colour that seem to move across its surface, while tourmaline forms as a transparent or translucent crystal in an astonishing variety of colours.

However, they share one important quality: individuality.

No two fine opals display precisely the same pattern. Meanwhile, tourmaline can occur in virtually every colour of the rainbow—sometimes with several colours appearing in a single crystal.

Therefore, anyone born in October has an almost endless range of possibilities.

Opal: A Rainbow Captured in Stone

Opal is one of nature’s most unusual gemstones.

Unlike gemstones such as diamond, sapphire or quartz, opal does not have a conventional crystalline structure. Instead, it consists primarily of hydrated silica, which means its structure contains water.

Opal forms when silica-rich water travels through cracks and spaces in rock and deposits tiny silica particles. Under the right conditions, these particles form arrangements that interact with light.

As a result, precious opal can produce its famous play-of-colour: moving flashes of blue, green, orange, yellow, violet and red.

Light diffracting through orderly arrangements of microscopic silica spheres creates this remarkable optical effect.

In other words, the colour is not painted onto the stone, nor does it come from coloured flecks trapped inside it. Instead, the interaction between light and the opal’s internal structure creates the colours we see.

Precious Opal and Common Opal

Not every opal displays play-of-colour. In fact, opal falls broadly into two groups: precious opal and common opal.

Precious Opal

Precious opal displays the shifting spectral colours for which this gemstone is famous. These flashes can appear as tiny pinpoints, broad patches, rolling colours or distinctive patterns.

Common Opal

In contrast, common opal does not display play-of-colour. Nevertheless, it can still be extremely attractive and occurs in beautiful shades of pink, blue, green, yellow, orange and white.

People sometimes overlook common opal because it lacks the famous rainbow effect. However, fine examples can make striking jewellery in their own right.

Different Types of Opal

Opal occurs in numerous varieties, each with its own distinctive character.

White Opal

White opal has a white or pale body colour and may display flashes from across the spectrum. It is also one of the most familiar varieties used in jewellery.

Black Opal

Black opal has a dark body colour, which allows its play-of-colour to appear particularly vivid.

Importantly, the term refers to the opal’s underlying body tone—not necessarily to a stone that appears completely black.

Fine black opal ranks among the most highly prized forms of opal. In particular, Lightning Ridge in New South Wales, Australia, is famous for producing exceptional examples.

Boulder Opal

Boulder opal forms in thin seams within ironstone. Cutters usually leave some of the natural host rock attached, both to support the opal and to showcase its pattern.

As a result, the contrast between dark ironstone and brilliant flashes of colour can produce dramatic and completely individual gems.

Crystal Opal

Crystal opal ranges from transparent to semi-transparent. Consequently, light can enter the stone and illuminate its play-of-colour.

Despite its name, however, crystal opal is not a crystal in the usual mineralogical sense.

Fire Opal

Fire opal has a yellow, orange or reddish body colour, and Mexico is particularly famous for producing it.

Some fire opals display play-of-colour, while others do not. Additionally, cutters may facet fine transparent examples rather than shaping them into traditional rounded cabochons.

What Determines an Opal’s Value?

Gemstone professionals do not value opal using exactly the same criteria they apply to diamonds or other transparent faceted gemstones.

Instead, important factors include:

• The brightness of its play-of-colour
• The range of colours present
• The pattern and distribution of colour
• Its body tone
• Transparency
• The amount of visible play-of-colour
• Stability and condition
• Natural, treated, synthetic or assembled status
• Overall beauty and desirability

Red flashes often attract particular interest because the internal structure required to produce them can also display other spectral colours. However, colour alone does not determine quality. For example, a beautiful blue-and-green opal can be far more desirable than a dull stone that contains only a small amount of red.

Ultimately, the complete appearance of an opal matters more than any single feature.

Solid Opals, Doublets and Triplets

Not every piece of opal jewellery contains one solid piece of opal. Therefore, understanding the difference between solid opals, doublets and triplets can help when choosing a piece.

Solid Opal

A solid opal comes from a single piece of natural opal material. With boulder opal, however, naturally attached host rock may remain part of the finished stone.

Opal Doublet

An opal doublet combines a thin slice of opal with a dark backing. This backing supports the opal and can also make its colour appear stronger.

Opal Triplet

An opal triplet contains a thin layer of opal between a dark backing and a transparent protective cap.

Both doublets and triplets can produce beautiful and affordable jewellery. They are not fake simply because they use assembled construction. However, sellers should always disclose that construction because it affects value, durability and care.

Natural, Synthetic and Imitation Opal

Not all opals on the market have the same origin. They may be natural, laboratory-created or made from imitation materials.

Manufacturers create synthetic opal to reproduce many of natural opal’s chemical, physical and optical characteristics. By contrast, imitation opal simply copies its appearance and may use materials such as glass, resin or plastic.

Some imitations look surprisingly convincing, particularly in photographs.

Therefore, confidently identifying an opal may require magnification, gemmological testing or examination by a qualified laboratory.

Bright colour alone does not prove that an opal is natural.

Is Opal Unlucky?

Opal has attracted centuries of mythology and superstition.

Ancient Romans treasured the gemstone and associated it with qualities such as hope, purity, truth, prophecy and protection. At other points in history, however, opal developed an undeserved reputation for bringing bad luck.

There is no factual reason to believe that opal is unlucky.

Instead, literature, changing fashions and commercial rivalry helped strengthen the superstition. Today, opal has reclaimed its place as one of the most distinctive gemstones in the natural world.

How to Care for Opal Jewellery

Because opal is softer and more delicate than many other gemstones, it requires a little extra care.

Opal measures approximately 5 to 6.5 on the Mohs hardness scale. Therefore, harder materials can scratch it. High heat or sudden temperature changes may also cause an opal to crack.

To care for opal jewellery:

• Clean it gently with warm, soapy water
• Use a soft cloth rather than abrasive materials
• Avoid steam and ultrasonic cleaners
• Protect it from sudden temperature changes
• Remove opal rings before heavy manual work
• Store opal separately from harder gemstones
• Avoid exposing doublets and triplets to prolonged soaking
• Have loose settings checked by a jeweller

Doublets and triplets need particular care because prolonged contact with water can weaken the adhesive that holds their layers together.

Tourmaline: A Gemstone in Almost Every Colour

While opal captivates with its play-of-colour, tourmaline offers an entirely different kind of variety.

Tourmaline is not simply one mineral. Instead, the name describes a complex group of closely related mineral species that share a similar crystal structure.

Different combinations of chemical elements can enter that structure as the crystals form. Consequently, tourmaline offers one of the broadest colour ranges of any gemstone family.

Tourmaline can be:

• Pink
• Red
• Green
• Blue
• Yellow
• Orange
• Brown
• Purple
• Black
• Colourless
• Multicoloured

Furthermore, some crystals display two or more distinct colours. This remarkable variety makes tourmaline an ideal October birthstone for anyone who refuses to choose a favourite.

Popular Tourmaline Varieties

Jewellers and gem dealers often use trade names to describe different colours and varieties of tourmaline.

Rubellite

Rubellite is a rich pink-to-red, purplish-red or reddish tourmaline.

However, not every pale pink tourmaline qualifies as rubellite. The name generally refers to stones with an attractive and reasonably saturated red or pinkish-red colour.

Indicolite

Indicolite refers to blue, greenish-blue or violetish-blue tourmaline.

Fine examples can display deep oceanic colours. However, very dark stones require careful cutting so that enough light can return to the viewer.

Green Tourmaline

Green tourmaline occurs in shades ranging from pale yellowish-green to deep forest green and vivid bluish-green.

As a result, the term covers an enormous range of material, from accessible commercial stones to exceptional collectors’ gems.

Chrome Tourmaline

Chrome tourmaline is particularly well known for its intense green colour.

Despite the name, vanadium may contribute more strongly to the colour than chromium in some stones.

Fine chrome tourmaline can resemble emerald or tsavorite garnet. Nevertheless, it remains a distinct gemstone with its own gemmological properties.

Paraíba Tourmaline

Paraíba tourmaline is famous for vivid blue, greenish-blue and blue-green colours produced by copper.

Miners first discovered the original material in the Brazilian state of Paraíba during the late 1980s. Later, miners also found copper-bearing tourmalines in Nigeria and Mozambique.

Fine copper-bearing tourmaline can display an almost neon-like colour and, consequently, may command exceptionally high prices.

However, not every blue-green tourmaline is Paraíba-type tourmaline. A gemmological laboratory may need to test a stone to confirm that copper causes its colour. Furthermore, determining geographic origin requires additional specialist analysis and may not always be possible.

Watermelon Tourmaline

Watermelon tourmaline displays pink or red in the centre with a green outer layer, creating an appearance reminiscent of a slice of watermelon.

Cutters often slice these crystals across their width to showcase the natural colour zoning.

As a result, watermelon tourmaline creates playful, distinctive jewellery that celebrates the enormous creativity of nature.

Parti-Coloured Tourmaline

Parti-coloured tourmaline displays two or more colours within a single stone.

Pink and green are common combinations, although tourmaline can form many other colour arrangements.

Rather than trying to produce an evenly coloured gem, the cutter may carefully orient the stone to preserve and highlight these natural colour zones.

Black Tourmaline

Black tourmaline is commonly associated with schorl, an iron-rich species of tourmaline.

It is usually opaque and can create bold, dramatic jewellery. Over time, it has also acquired numerous symbolic and spiritual associations. However, these beliefs represent traditions rather than scientifically established effects.

What Determines Tourmaline’s Value?

Colour generally plays the most important role in determining the quality and value of tourmaline.

Buyers may consider:

• Hue, tone and saturation
• Brightness and liveliness
• Clarity
• Cut quality
• Carat weight
• Colour zoning
• Natural or laboratory-grown status
• Detectable treatments
• Copper content in Paraíba-type material
• Geographic origin when relevant and reliably documented
• Overall beauty and market demand

Bright, saturated colours that do not appear overly dark often attract the greatest demand.

However, beauty remains subjective. For example, earthy green, smoky pink and multicoloured stones may appeal more strongly to someone who prefers subtle or unusual jewellery.

Therefore, a gemstone does not need to represent the most expensive variety to be beautiful.

Inclusions in Tourmaline

Tourmaline often forms in fluid-rich environments, and crystals can trap some of that material as they grow.

Consequently, tourmaline may contain:

• Thread-like internal tubes
• Liquid inclusions
• Crystals
• Growth features
• Partially healed fractures

Buyers and gem professionals often accept inclusions more readily in red and pink tourmaline than in green or blue material.

Interestingly, some tube-like inclusions can create a cat’s-eye effect when a cutter shapes the stone as a cabochon. Gemmologists call this moving line of reflected light chatoyancy.

As with all gemstones, however, inclusions should be assessed for their effect on beauty and durability rather than automatically treated as defects.

Is Tourmaline Treated?

Gemstone processors may use heat or irradiation to alter or improve tourmaline’s colour.

Because ordinary equipment cannot always detect these treatments, significant stones may require assessment by a recognised gemmological laboratory.

Treatment does not automatically make a gemstone undesirable. However, sellers should disclose known treatments because they may affect price, rarity and care.

Similarly, a seller should never describe a gemstone as untreated without a reasonable basis for making that claim.

How to Care for Tourmaline Jewellery

Tourmaline measures approximately 7 to 7.5 on the Mohs hardness scale. Therefore, it is harder than opal and generally suitable for many types of jewellery. Nevertheless, sensible care will help protect it.

To care for tourmaline jewellery:

• Clean it with warm, soapy water and a soft brush
• Avoid steam cleaners
• Avoid ultrasonic cleaning, especially when inclusions or fractures are present
• Protect it from sudden temperature changes
• Remove rings before heavy work
• Avoid exposing the gemstone to unnecessary heat during repairs
• Store it separately to prevent scratches

Tourmaline generally remains stable in normal light and during ordinary wear. However, excessive heat may damage the gemstone or alter certain treated colours.

Opal or Tourmaline: Which October Birthstone Should You Choose?

There is no wrong answer. Ultimately, your choice comes down to the colours, characteristics and style that appeal to you most.

Choose Opal If You Love:

• Dreamlike flashes of rainbow colour
• Soft, organic shapes
• Gems in which no two patterns are alike
• Antique and artistic jewellery
• A stone with an almost otherworldly appearance

Choose Tourmaline If You Love:

• Transparent, sparkling gemstones
• A huge variety of colours
• Pink, green, blue or multicoloured jewellery
• More durability for frequent wear
• Unusual varieties such as watermelon or Paraíba-type tourmaline

Of course, you can also choose both.

After all, birthstone traditions should make jewellery personal and enjoyable. You do not have to wear only one prescribed colour or gemstone simply because you were born in a particular month.

Buying October Birthstone Jewellery

Whether you choose opal or tourmaline, knowing what you are buying matters. Therefore, before purchasing October birthstone jewellery, consider asking the seller:

• Is the gemstone natural, synthetic or an imitation?
• Has it received any known treatment?
• Is the opal solid, a doublet or a triplet?
• Is the stated variety name accurate?
• Has a valuable stone been independently tested?
• Are there fractures or inclusions that may affect durability?
• Is the setting suitable for the gemstone?
• What cleaning and care does the piece require?

Descriptions such as “natural,” “untreated,” “Paraíba” and “black opal” can materially affect a gemstone’s value. Therefore, sellers should use these terms carefully and support them with appropriate expertise or documentation.

Happy Birthday to Our October Founder

October already gives us two extraordinary birthstones, but here at Alex Ruby it also gives us an excellent reason to celebrate.

Our founder Allie celebrates her birthday on 13 October.

Her love of jewellery, vintage treasures, gemstones and the stories carried by beautiful objects lies at the heart of what Alex Ruby represents. Consequently, the extraordinary individuality of opal and the endless variety of tourmaline feel like especially fitting birthstones.

So, from everyone at Alex Ruby Trading Co.:

Happy birthday, Allie!

And happy birthday to every October baby whose personality—like their birthstones—cannot possibly be represented by only one colour.

Final Thoughts on October Birthstones

Opal and tourmaline make perfect companions for October.

On one hand, opal captures shifting rainbows within a gemstone. On the other, tourmaline offers nearly every colour imaginable. One fascinates us with its play-of-colour and unusual internal structure, while the other showcases a remarkable combination of chemistry and variety.

Together, they remind us that gemstone beauty cannot be reduced to size or price alone.

Instead, we find beauty in colour, pattern, rarity, craftsmanship, individuality and, ultimately, the way a jewel makes its owner feel.

Whether you choose a fiery black opal, a delicate pink tourmaline, a slice of watermelon colour or a treasured vintage opal ring, October’s birthstones offer a world of possibilities.