Hardness & Durability, Compared
"Will it last?" is really two questions: does it resist scratching (hardness) and does it resist chipping (toughness)? Stones can be strong at one and weak at the other.
The Mohs scale, with the numbers that matter
| Material | Mohs | Daily-wear verdict |
|---|---|---|
| Diamond — mined or lab-grown | 10 | The reference point. Scratched only by another diamond. |
| Moissanite | 9.25 | Fully engagement-ready; a lifetime stone. |
| Sapphire / Ruby | 9 | Excellent for daily rings. |
| Emerald | 7.5–8 | Wearable with care; prefers protective settings. |
| Quartz (amethyst, citrine) | 7 | The floor for ring stones; occasional wear. |
| Household dust (silica) | ≈ 7 | The quiet enemy — this is why soft stones haze. |
| Opal / Pearl | 2.5–6.5 | Earrings and pendants, not daily rings. |
The scale is ordinal, not linear: diamond at 10 is several times harder than sapphire at 9, not 11% harder.
Hardness ≠ toughness
Diamond is the hardest material on earth yet can still chip if struck precisely on a girdle edge or exposed point — which is why pears get V-tip prongs and princess corners get cover. Jade, famously, is only Mohs 6–7 but nearly unbreakable. Settings exist to manage exactly this: bezels protect edges, six prongs beat four for security, and low profiles dodge door frames.
Metal durability, briefly
All jewelry metals scratch — a scratch is metal displaced, not lost, and polishing redistributes it. Ranked for daily hardiness: 10k ≥ 14k > 18k > sterling silver. Full detail in the metal guide.
What we'd tell a friend
- Engagement ring worn every day, forever: diamond (lab or natural), moissanite, or sapphire. Full stop.
- Softer stones you love — emerald, opal, pearl: wear them, but in pendants, earrings, or rings you remove for gym, garden and dishes.
- Whatever the stone: an annual prong check (ours is complimentary) prevents nearly every heartbreak we see.
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