How to Choose a Gemstone: A Guide to Sapphire, Opal, Pearl & Tourmaline

Choosing a gemstone for a piece of fine jewellery is one of the most personal decisions you can make. Whether you're commissioning a bespoke engagement ring, a birthday gift, or a piece to mark a milestone, the gemstone you choose will carry meaning for a lifetime. This guide walks through four of our most beloved gemstones — sapphire, opal, pearl, and tourmaline — so you can make an informed, confident choice.

Sapphire

Sapphire is the quintessential fine jewellery gemstone: deeply saturated, brilliantly durable (9 on the Mohs scale), and steeped in meaning. While cornflower blue sapphires from Sri Lanka (originally Ceylon) remain the most coveted, sapphires come in virtually every colour including pink, yellow, teal, white, and the rare padparadscha, a delicate peach-pink prized above all others.

What to look for: colour saturation and evenness, clarity (eye-clean is the benchmark for faceted stones), and cut quality, which determines how light moves through the stone. Australian sapphires, sourced from Queensland and New South Wales, offer a distinctive deep blue-green tone that suits modern, nature-inspired designs beautifully.

Sapphire suits everyday fine jewellery because of its hardness — rings, bracelets, and pendants worn daily will not scratch easily.

Opal

One of Venetia's personal favourites, that play-of-colour, the rolling flash of red, green, and violet across the stone's surface is just magnificent.  Formed by microscopic silica spheres diffracting light, making opal one of the most visually arresting gemstones in existence. Australia produces over 90% of the world's fine opals, including the legendary black opals from Lightning Ridge and the brilliant crystal opals of Coober Pedy.

What to look for: brightness and coverage of colour play, body tone (darker body tones make colour play pop), and pattern — broad flash, harlequin, and rolling flash patterns are among the most desirable. Opals are softer (5.5–6.5 on the Mohs scale) and should be set thoughtfully to protect the stone — bezel settings and pendants work particularly well.

Opal suits those drawn to one-of-a-kind, organic beauty. A bespoke opal piece is genuinely irreplaceable.

Pearl

Pearls occupy a unique place in fine jewellery — they are the only gemstone grown by a living creature. Cultured South Sea pearls, produced by the Pinctada maxima oyster in the warm waters of Australia's north-west coast, are among the largest and most lustrous in the world. Their satiny glow — known as orient — is produced by hundreds of thin layers of nacre built up over years.

What to look for: lustre (a high-lustre pearl will reflect your face like a mirror), surface quality (minor blemishes are natural and acceptable; deep pits or cracks are not), size, and shape. Rounds are classical; drop and baroque shapes suit sculptural, contemporary designs.

Pearl suits those who appreciate quiet luxury. A pearl pendant or ring has an understated elegance that transcends trends.

Tourmaline

Tourmaline is the gemstone for colour lovers. Its range is extraordinary: from Paraíba tourmaline's electric neon blue-green (some of the most expensive gemstones per carat in the world) to the deep raspberry of rubellite, the verdant chrome tourmaline, and the bi-colour or watermelon varieties that shift from pink to green within a single crystal. Tourmaline scores 7–7.5 on the Mohs scale, making it suitable for most jewellery types with reasonable care.

What to look for: colour vibrancy and saturation, cut (tourmaline is often cut to maximise colour rather than brilliance), and clarity. Inclusions are common in some varieties and are acceptable as long as they don't compromise the stone's structural integrity.

Tourmaline suits collectors and those who want something genuinely unexpected — a piece that reflects a distinctive, considered aesthetic.

How to Choose

The right gemstone is the one that resonates with the person who will wear it. Consider:

• Lifestyle: How active are you? Softer stones like opal and pearl need more protection than sapphire or tourmaline.
• Colour: What colours do you gravitate toward in your wardrobe and home? A gemstone worn daily should feel natural alongside your existing palette.
• Meaning: Birthstones, anniversary stones, and stones associated with particular qualities (sapphire for loyalty, pearl for wisdom, tourmaline for creativity) add a layer of intention to a piece.
• Budget: Carat weight, origin, and treatment status all affect price. An untreated sapphire from a fine origin will command a premium; a beautiful Australian opal can be more accessible while remaining exceptional.

If you're uncertain, we'd love to help. Every bespoke piece at Venetia Major - Bespoke Jewellery  begins with a conversation — about the person, the occasion, and the story you want the jewellery to tell. Get in touch to book a design appointment and we'll guide you through the selection process from the very beginning.