How to Choose a Coloured Gemstone for Your Engagement Ring

By Dr Petré Prins

For centuries, natural diamonds have been the first choice as a betrothal gift amongst royalty. In the late 1940s, an extensive marketing campaign by De Beers promoting diamonds as a symbol of love and engagement cemented a diamond ring as the ultimate token of commitment.

While diamonds remain timeless, more couples are choosing to express their personalities and love stories through other gemstones that offer unique colours, meanings, and more affordable prices. If you are exploring alternatives, you can view our collection of Gemstone Engagement Rings on the Prins & Prins website to see how coloured gems can be used in elegant, durable designs.

Your Personal View

Firstly, you and your partner should decide what the ring means, and then select a gemstone that is within your budget and reflects your style, your story, and your love. Decide whether you want a ring with emotional meaning and inherent value, or whether you prefer size and more visual impact for your budget. Then find the right gem by considering its Durability, Rarity, Beauty and Symbolism.

Durability

The Mohs hardness scale ranks minerals on a non-linear scale from 1 to 10, with diamond as the hardest (10). Sapphire and ruby have a hardness of 9. For daily wear, gemstones with a hardness greater than 7.5 are recommended. If you have an active lifestyle, only diamond, sapphire or ruby will suffice.

Rarity

Your engagement ring symbolises a unique love between two people and will serve as a valuable memento to your children. Choose a natural gemstone that has inherent rarity and value, because a synthetic diamond, sapphire or ruby has no rarity and cannot serve as an heirloom.

Beauty

Consider whether you prefer the traditional brilliance of a white or yellowish diamond, or the rich hues and natural beauty of coloured gems. Your ring should reflect your unique personality and relationship, whether that means a classic look or something distinctive.

Symbolism

In most cultures, gemstones are spiritually tied to meanings such as healing, protection, love and wisdom. If both of you value symbolism, choose a coloured gemstone that offers more than beauty. For instance, sapphire symbolises loyalty, truth and commitment.

Sapphire

Hardness: 9Toughness: ExcellentBrilliance: GreatCleavage: NoneColours: Blue, white, green, orange, purple, pink, yellow, pink-orange

Spinel

Hardness: 8Toughness: GoodBrilliance: GreatTreatments: NoneCleaner inside than most rubies and sapphiresColours: Whites, light pinks and blues, glamorous greys, neon pink, orange, pink-orange, traffic-light redSpinel offers exceptional brilliance and durability, yet remains one of the gemstone world’s best-kept secrets.

Diamond

Hardness: 10Toughness: Fair to GoodCleavage: PerfectBrilliance and Fire: ExceptionalColours: Colourless, brownish, yellowish, and rare fancy colours

Ruby

Hardness: 9Toughness: ExcellentBrilliance: GreatCleavage: NoneColours: Red, pinkish-red

Garnet

Hardness: 7 to 7.5Toughness: GoodTreatments: NoneBrilliance: GreatFar cleaner inside than emeralds

Varieties:• Tsavorite: Grass green to mint green; expensive above 1ct• Mandarin Garnet: Bright orange to brownish orange• Rhodolite: Darker pink to purplish red• Demantoid: Green to yellowish green; high dispersion and colour flashes; rare• Pyrope: Dark red to brownish red; very affordable

Chrysoberyl

Hardness: 8.5Toughness: VariesBrilliance: GreatTreatments: NoneColours: Golden yellow, green-yellow, greenOften cut as a cabochon with a striking cat’s-eye effect.

Coloured Gems Not Suitable for Engagement Rings

Cultured Pearls

Hardness: 2.5 to 4Toughness: Poor to FairBeautiful with much meaning, but scratches easily.

Opal

Hardness: 5.5 to 6.5Toughness: Poor to FairIt can fracture with high heat or sudden temperature changes.

Moonstone

Hardness: 6 to 6.5Toughness: PoorCleavage: Perfect, meaning it breaks cleanly when struck.

Morganite

Hardness: 7.5 to 8Toughness: Fair to GoodLess brilliance and lustre; commercial stones are often pale pink.

Tanzanite

Hardness: 6 to 6.5Toughness: Fair to PoorPerfect cleavage; fractures easily.

Blue Topaz

Hardness: 8Toughness: PoorCleavage: PerfectTreated and may be radioactive.

Emerald

Hardness: 7.5 to 8Toughness: Fair to GoodHeavily included, treated, and brittle.

Tourmaline

Hardness: 7 to 7.5Toughness: FairRed and pink varieties are heavily included.

Choosing Your Perfect Coloured Gem

Ultimately, the choice of gemstone is a personal one, but for daily wear, it is advisable to select gems higher on the Mohs scale. Whether you are drawn to the serene blue of a sapphire or the romantic red of a ruby, let both your heart and your lifestyle guide your decision.

At Prins & Prins, every coloured gemstone above one carat is certified natural and accompanied by a grading report from a GIA graduate gemmologist. Our experts will guide you in selecting the perfect gem, and our master goldsmiths will craft a bespoke engagement ring that is as enduring and individual as your love.

Explore the beauty of natural colour, and design your forever ring at Prins & Prins, Cape Town’s specialists in natural gemstone engagement rings.