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.
Amber is soft compared to gem minerals and many other organics. It falls between 2 and 2.5 on the Mohs scale. Amber also has poor toughness, so care must be taken when wearing amber not to scratch and damage it.
Amber burns at relatively low temperatures. With prolonged exposure to light it might darken, and it can be damaged by chemicals.
The only safe way to clean amber is with warm, soapy water. Be sure to use a mild soap.
Treatment and durability considerations
The dyes used to color amber are not stable and can change or fade under certain circumstances.