Beyond Diamond: The Case for Coloured Gemstones
The shift away from diamond as the default engagement ring stone has opened genuine conversations about coloured gemstones — and in South Africa especially, where tanzanite is mined, sapphires have deep cultural resonance, and individual expression is increasingly valued over convention, alternative stones deserve serious consideration.
This guide covers the most popular alternative gemstones for engagement rings — their properties, their practical suitability for daily wear, their price range in South Africa, and where Heritage & Co. currently fits into this picture.
The Most Important Factor: Hardness
Before choosing any gemstone for an engagement ring, understand the Mohs hardness scale. This measures a stone's resistance to scratching — and since engagement rings are worn daily, often while doing household tasks, cooking, exercising, and working, hardness is not a trivial consideration.
| Gemstone | Mohs Hardness | Daily Wear Suitability |
|---|---|---|
| Diamond | 10 | Excellent |
| Moissanite | 9.25 | Excellent |
| Ruby | 9 | Very Good |
| Sapphire (all colours) | 9 | Very Good |
| Tanzanite | 6–7 | Moderate — requires care |
| Emerald | 7.5–8 | Moderate — typically included |
| Opal | 5.5–6.5 | Poor — too soft for daily wear |
| Pearl | 2.5–4.5 | Very Poor — not suitable |
The practical rule: for a ring worn every day, you want a stone with a Mohs hardness of 8 or above. Anything softer should be reserved for pendants, earrings, or rings worn occasionally — not a daily engagement ring.
Blue Sapphire
Blue sapphire is the most popular alternative engagement ring stone globally, famously associated with Princess Diana and Kate Middleton's engagement ring. Corundum (the mineral family of both sapphire and ruby) at Mohs 9 is genuinely suitable for daily wear.
Colours available: Sapphire comes in virtually every colour — blue (most traditional), pink, yellow, white, orange (padparadscha), teal, and green. White sapphire is sometimes marketed as a diamond alternative — it's a legitimate stone but lacks the brilliance of diamond or moissanite.
South African pricing: Natural blue sapphires in fine quality (2ct+, deep saturated colour, minimal inclusions) are expensive — comparable to or exceeding lab-grown diamond pricing. Lab-created sapphires offer the same physical properties at significantly lower prices, typically R8,000–R25,000 for a 2ct stone in solid gold.
Best settings for sapphire: Bezel settings offer the best stone protection. Four or six prong solitaires work well. Avoid settings that leave the girdle exposed on daily-wear rings.
Ruby
Ruby (red corundum) carries significant cultural and emotional weight — in many African traditions, red stones symbolise passion, vitality, and commitment. At Mohs 9, ruby is suitable for daily wear.
Quality consideration: Fine natural rubies of significant size are exceptionally rare and expensive — often more valuable per carat than diamonds of equivalent grade. Most rubies sold commercially are heat-treated to improve colour and clarity. This is standard practice and not considered deceptive — but it should be disclosed by any reputable seller.
Lab-created rubies offer the same physical and optical properties as natural ruby at dramatically lower prices. A 2ct lab ruby in a 14k gold setting can be sourced for R12,000–R20,000.
Pairing advice: Ruby in yellow gold is a classic, warm combination. Ruby in white gold or platinum creates a bold high-contrast look. Rose gold and ruby can feel overly matchy — use judiciously.
Tanzanite: Uniquely African, With Real Caveats
Tanzanite is found only in a small area near Mount Kilimanjaro in Tanzania — it is one of the rarest gemstones in the world, with estimated reserves that may be exhausted within decades. Its trichroic optical properties (showing blue, violet, and burgundy under different lights) make it visually extraordinary.
The daily wear problem: At Mohs 6–7, tanzanite is significantly softer than diamond, moissanite, sapphire, or ruby. Daily wear as an engagement ring solitaire will result in visible surface scratching over 5–10 years. The stone will need periodic re-polishing to restore its surface.
Our honest recommendation: Tanzanite is spectacular — but it is better suited to pendants, earrings, or right-hand rings worn on special occasions rather than a daily engagement ring. If you love tanzanite and want it as an engagement ring, consider a protective bezel setting and be prepared for periodic maintenance.
South African pricing: High-quality tanzanite (AAA grade, deep blue-violet, 2ct+) can range from R15,000–R60,000 depending on quality and origin certification. Its rarity does give it stronger secondary market characteristics than most gemstones.
Emerald
Emerald's deep green has made it one of the most beloved gemstones historically — Cleopatra famously favoured it. Colombia produces the finest examples. However, emerald presents real durability challenges for daily wear.
Most emeralds contain natural inclusions (the industry term is "jardin" — garden) that are considered part of the stone's character. Many are also fracture-filled with oil or resin to improve clarity. This treatment is industry-standard but makes emeralds more sensitive to ultrasonic cleaners and certain chemicals.
Our recommendation: Emerald as an engagement ring is achievable but requires committed care. A bezel setting protects the stone better than prongs. Avoid harsh chemicals, ultrasonic cleaners, and steam cleaning. If you love the emerald-cut shape but want diamond-level durability, consider a moissanite or lab diamond in an emerald cut instead.
Does Heritage & Co. Offer Coloured Gemstone Rings?
Our current core collection focuses on moissanite and lab-grown diamond — colourless stones in solid gold settings. This is deliberate: our quality standards, certification processes, and durability guarantees are built around these stone categories.
For coloured gemstone requests, we handle these through our custom design process on a case-by-case basis. We can source certified sapphires, rubies, and selected other stones through our supplier network and set them in Heritage & Co. gold settings to our standard quality.
If you're interested in a coloured gemstone ring, WhatsApp us at +27 82 818 9106 and we'll discuss what's possible, realistic pricing, and whether the stone you have in mind is suitable for daily wear.
For those who love the idea of a non-traditional look within our standard range, our moissanite collection includes oval, marquise, pear, and emerald-cut stones — shapes that read as distinctive and non-conventional while delivering the durability of a 9.25 Mohs stone.