Material Standard // 05

Hardness, toughness,
care.

Colored stones differ far more than diamonds do in how they wear. Hardness, toughness and care decide where a stone belongs: on a ring that meets the world all day, or on earrings and pendants that are more protected.

Hardness and toughness

Hardness, measured on the Mohs scale from 1 to 10, is resistance to scratching. Toughness is resistance to chipping and breaking. A stone can be hard but brittle, so both matter.

Stone	Mohs hardness	Wear
Diamond	10	Suited to every kind of jewelry
Sapphire and ruby	9	Excellent for rings
Topaz	8	Good; avoid sharp knocks
Emerald	7.5 – 8	Often has inclusions; protective settings and gentle care
Aquamarine	7.5 – 8	Good for most jewelry
Garnet	6.5 – 7.5	Good for most jewelry
Amethyst and citrine	7	Good for most jewelry
Onyx	6.5 – 7	Good; keep away from harder stones
Peridot	6.5 – 7	Better in earrings and pendants
Opal	5.5 – 6.5	Delicate; protective settings
Pearl	2.5 – 4.5	Delicate; last on, first off

Treatments

Many colored stones are treated to improve their color or clarity; heating sapphire and oiling emerald are long-established examples. Where a Peelerie piece is set with a colored stone, its product page names the stone.

Plate IIThree faceted colored gemstones in a row, a blue sapphire, a red ruby and a green emerald

Care

Clean colored stones with warm water, mild soap and a soft brush. Avoid ultrasonic cleaners and steam for emeralds, opals, pearls and onyx, and keep pieces apart from harder stones that can scratch them.