Opal
Natural stone
Silica with water held in it, many with a play of colour. Sensitive to heat, sudden temperature changes, knocks and drying out – never ultrasonic or steam.
Hardness (Mohs): 5.5–6.5
Natural stone
Silica with water held in it, many with a play of colour. Sensitive to heat, sudden temperature changes, knocks and drying out – never ultrasonic or steam.
Hardness (Mohs): 5.5–6.5