Hardness and toughness
Gem and mineral hardness is measured on the Mohs scale. The numbers are based on the relative ease or difficulty with which one mineral can be scratched by another. But the Mohs scale is deceptive. The steps between the minerals are not evenly spaced. For example, diamond is only one number away, but it’s many times harder than gems in the corundum family.
Jadeite is 6.5 to 7 and nephrite is 6 to 6.5 on the Mohs hardness scale, so some care should be taken to avoid scratches. However, both of these gemstones have exceptional toughness and are very resistant to breaking or chipping.
Heat from a jeweler’s torch can harm jade. Jade is stable to light, and it can be affected by warm acids.
Ultrasonic cleaners and steam cleaners are safe for untreated jade. But jade might be treated by dyeing, bleaching and impregnation, coatings, or heat treatment, so warm, soapy water is always a safe choice.