Gemstone Hardness Chart: Which Stones Suit Rings?

Hardness tells you how well a stone resists scratching. It is the single best predictor of whether a stone will still look good after ten years of wear.

The chart

• 10 — Diamond (lab-grown and mined)
• 9.25 — Moissanite
• 9 — Ruby, Sapphire
• 8.5 — Alexandrite
• 7.5–8 — Emerald, Zircon, Tourmaline (including paraiba)
• 7 — Quartz, Amethyst

What the numbers mean for wear

Anything at 8.5 or above is safe in a ring worn every day. Stones at 7.5–8 are fine in rings if the setting protects them, and ideal in pendants, earrings and necklaces — which take far fewer impacts.

The setting matters as much as the stone

A bezel or channel setting shields a stone's edges and girdle; high prongs expose them. A 7.5 stone in a bezel often outlasts a 9 stone in tall, thin prongs.

Practical guidance

• Daily-wear engagement ring: moissanite, diamond, ruby, sapphire
• Occasional-wear ring: emerald, paraiba, zircon (bezel recommended)
• Any setting: pendants, earrings, necklaces

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