The best stones for engagement rings
Most engagement rings are still center-stone diamonds for the obvious reason — diamond is the hardest material a customer can wear daily. But about a third of the rings we sell are colored stones, and the trade-offs are worth taking seriously rather than assuming "diamond or nothing."
The ranking below is for daily wear — the constraint is hardness above all, because a stone that picks up abrasion on year three is the sort of regret no setting can fix. Hardness on the Mohs scale:
- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 9
- 10
Everyday wear comfortably wants a 7+. Below 7, choose settings that protect the stone (bezel, halo) and store the piece carefully.
The ranking
| Hardness | Why it works | What to know | |
|---|---|---|---|
| Diamond | 10 | Unmatched hardness, unmatched sparkle, deepest secondary market | The default for a reason. Lab-grown lets you double the visible size for the same budget. |
| Sapphire | 9 | Almost as hard as diamond; comes in every color; takes a heat treatment that stabilizes color permanently | Don't sleep on Montana teal sapphires for something distinctive. See the sapphire guide. |
| Ruby | 9 | Same hardness as sapphire (it is sapphire, technically); rich color | Burmese rubies hold value best. Insist on a lab report disclosing treatments — heat is fine, lattice filling is not. |
| Moissanite | 9.25 | Harder than sapphire; brighter fire than diamond; cheaper than both | Sparkles differently — more "rainbow" than diamond's white fire. You either love it or you don't. |
| Aquamarine | 7.5–8 | Underrated for engagement rings; soft cool blue, almost always eye-clean | Pair with a protective setting (bezel or partial halo). Soft enough to scratch over a 30-year horizon. |
| Spinel | 8 | Naturally colored (no treatment); historically mistaken for ruby — including the British Crown Jewels | An expert-level pick. Hard, rare, fully natural, often priced below sapphire for similar color. |
| Topaz (imperial) | 8 | Warm peach to pink color; harder than emerald | Cleavage planes — avoid sharp impact. Set with a halo or bezel for daily wear. |
| Emerald | 7.5–8 | The most coveted green; rich color even in smaller stones | Almost always oil-treated. Treat gently — no ultrasonics, no harsh chemicals. A daily-wear emerald needs a protective setting and willingness to re-oil every few years. |
| Tourmaline | 7–7.5 | Every color, often two in one stone (watermelon) | Just at the hardness threshold for daily wear. Bezel or protected halo settings preferred. |
What to skip for daily wear
These show up in engagement-ring searches but are honest mistakes for an everyday piece. Use them in earrings, pendants, or cocktail rings:
- Opal (Mohs 5.5–6.5) — water-sensitive, cleaves easily. A showstopper as a special-occasion stone; a heartbreak as an engagement ring.
- Pearl (Mohs 2.5–4.5) — too soft for any setting that touches a hard surface daily.
- Turquoise (Mohs 5–6) — porous, sensitive to oils, prone to color fading.
- Tanzanite (Mohs 6.5–7) — has perfect cleavage and reacts poorly to sudden temperature changes. Beautiful, but not for daily wear.
The case for non-diamond
You see colored stones gaining share in engagement rings every year. The reasons:
- Visual identity. A teal Montana sapphire reads as personal in a way a white diamond does not.
- Birthstone or sentimental link. A gift that nods to a birthday or an heirloom carries narrative weight.
- Budget. A sapphire engagement ring at the same total price as a diamond comparable buys a substantially bigger center stone and a stronger setting.
- Concern over the diamond industry. Mining, lab-grown environmental footprint, marketing-engineered demand — all valid factors. A colored stone with full origin disclosure sidesteps the debate.
The right reason to choose any stone, including diamond, is that the person wearing it will love it for fifty years.
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Written by
Anna
Jeweler · Formi Jewelry
Anna works with Formi clients on stone selection, setting design, and fit — making sure every piece is right before it’s made.
Book a consultation with our in-house jewelersLast updated May 2026