October is one of the few months graced with two birthstones — opal and tourmaline. Both gems captivate with mesmerising colour, yet they differ entirely in composition, character, and care. Choosing between them is less about fashion and more about personal expression. At Prins & Prins Diamonds, our gemmologists often help clients navigate this decision, balancing beauty with practicality to find the jewel that truly reflects their individuality.
Formation and Composition — Nature’s Contrasts
Though united by their brilliance, opal and tourmaline are born of very different geological stories.
Opal is the result of water and silica slowly binding together in the crevices of rocks over millions of years. What makes opal so extraordinary is its play-of-colour — a shifting kaleidoscope of light caused by microscopic spheres of silica diffracting colour. Each opal is unique, its patterns forming like fingerprints of the Earth. The most prized opals come from Lightning Ridge in Australia and the Welo region of Ethiopia, with African sources now adding their own distinctive charm.
Tourmaline, by contrast, is a crystalline borosilicate mineral rich in trace elements such as iron, lithium, and manganese. Its complex structure allows it to occur in almost every hue imaginable — from verdant green to vivid pink and neon blue. Some even display multiple colours in a single crystal, as in the much-loved watermelon tourmaline. Fine specimens are found in Mozambique, Namibia, and Brazil, continuing Africa’s legacy as a source of exceptional gems.“No two gemstones are ever alike,” explains one of our gemmologists. “Opal captures light in motion; tourmaline holds colour in permanence. One is the poetry of reflection, the other the science of saturation.”
Durability and Care — Understanding Practical Differences
When selecting a gemstone, it is essential to understand its strength and care requirements. Opal and tourmaline vary noticeably in durability.
Opal is relatively soft, measuring around 5.5 to 6.5 on the Mohs scale. Because it contains up to 20% water, it is sensitive to dryness, heat, and sudden temperature changes. If exposed to harsh conditions, it can lose moisture, develop cracks, or dull in lustre. For this reason, opals are best suited to pieces that avoid daily wear — such as earrings, pendants, or brooches. To preserve their beauty, store them in a soft cloth, away from direct sunlight, and avoid strong detergents or ultrasonic cleaning.
Tourmaline, in comparison, ranks 7 to 7.5 on the Mohs scale, making it considerably harder and better suited for everyday jewellery like rings or bracelets. It is resilient but not indestructible — even durable gemstones benefit from regular inspection and gentle cleaning.
In essence, opal asks for tenderness; tourmaline rewards reliability.
Varieties and Colour Stories
One of the joys of October’s twin birthstones is their endless variety.
Opal varieties include:
- White Opal – soft milky body colour with pastel flashes.
- Crystal Opal – transparent or translucent with vivid play-of-colour.
- Black Opal – the most valuable, with dark body tones that amplify colour.
- Boulder Opal – formed within host rock, often displaying striking natural patterns.
Black opals from Lightning Ridge are particularly prized for their dramatic contrast, while Ethiopian opals are celebrated for their fiery, shifting hues and remarkable transparency.
Tourmaline varieties range just as widely:
- Rubellite (red-pink) – vibrant and romantic.
- Indicolite (blue) – deep oceanic tones, rare and sophisticated.
- Paraíba (neon turquoise-green) – famed for its electric glow, among the world’s most coveted gems.
- Green, Chrome, and Bi-colour Tourmaline – lively, natural, and highly wearable.
Collectors and designers often admire tourmaline’s stability of colour under varied lighting — where opal dances, tourmaline radiates.
“In opal, we look for broad, consistent flashes of spectral colour,” notes a Prins & Prins gemmologist. “In tourmaline, we seek pure, saturated tones with even distribution and minimal inclusions.”
Symbolism and Meaning
Throughout history, opal and tourmaline have carried distinct symbolic associations.
Opal represents creativity, emotion, and transformation. Its ever-changing colours mirror the human spirit — imaginative, passionate, and expressive. Many believe opal enhances inspiration and strengthens emotional connection, making it a favourite among artists and dreamers.
Tourmaline, conversely, symbolises balance, protection, and understanding. Because it can display several colours within one crystal, it is seen as a harmoniser — a gemstone that bridges opposites and promotes calm.
Both gems, in their own way, express individuality: opal for those who value fluidity and expression, tourmaline for those drawn to depth and composure.
Choosing the Right Gem for Your Jewellery
Selecting between opal and tourmaline often depends on lifestyle, design preference, and how you intend to wear your jewel.
For statement pieces such as pendants or cocktail rings, opal’s kaleidoscopic beauty creates unmatched drama. It pairs exquisitely with yellow or rose gold, which amplifies its warmth and vintage charm. However, these should be reserved for occasional wear and handled with care.
For everyday jewellery, tourmaline is the more practical choice. Its durability allows it to shine in engagement rings, bracelets, and contemporary designs. Green and pink tourmalines look particularly elegant in white gold or platinum settings, while Paraíba tourmaline stands out beautifully against rose gold.
Both gemstones complement diamonds remarkably well — opal through contrast, tourmaline through harmony — allowing designers to create pieces that feel both timeless and individual.
For clients uncertain which gem best suits their lifestyle or taste, Prins & Prins gemmologists offer personalised guidance, ensuring that every jewel is chosen with knowledge and confidence.
Expert Tips on Evaluating Quality
When assessing opal, consider:
- The intensity and range of colour visible under light.
- The pattern (broad flashes are rarer and more valuable than pinfire).
- The body tone — darker tones increase vibrancy and contrast.
When evaluating tourmaline, look for:
- Even colour saturation from every angle.
- Clarity, with minimal inclusions.
- Precision of cut, which maximises brilliance and depth.
At Prins & Prins, all opals and tourmalines are examined and certified by qualified gemmologists, ensuring authenticity, provenance, and natural origin. Transparency in evaluation builds trust — a cornerstone of our heritage as Cape Town’s premier jeweller.
Conclusion — Expertise You Can Trust
Opal and tourmaline may share a birth month, but each tells a different story. One is delicate and poetic; the other strong and grounded. Both are beautiful, valuable, and profoundly personal.
Whether you are drawn to opal’s shifting fire or tourmaline’s steadfast glow, let knowledge guide your choice. At Prins & Prins Diamonds, our gemmologists combine scientific precision with artistic appreciation to help you select a gem that reflects not only your style but your spirit.
Discover their radiant diversity in our curated collection of Gemstone Jewellery — where authenticity, craftsmanship, and heritage converge in every creation.
