Resin is a durable and transparent plastic that is especially suited for jewelry-making because of its ease of use. It begins in a liquid form, but after being casted, becomes quite durable. Special resin molds with smooth surfaces are created to give it a glossy finish.
Amber is fossilized tree resin (not sap), which has been appreciated for its color and natural beauty since Neolithic times. Much valued from antiquity to the present as a gemstone, amber is made into a variety of decorative objects. The abnormal development of resin in living trees (succinosis) can result in the formation of amber. Inclusions of other substances can cause amber to have an unexpected color. Pyrites may give a bluish color. Bony amber owes its cloudy opacity to numerous tiny bubbles inside the resin.