The essence is used to coat glass or plastic beads to manufacture artificial pearls. A thick coating of pearl essence can make the fake look very realistic. Fake pearls are easy to detect. They feel smooth if gently drawn across the edge of your teeth. Natural and cultured pearls feel gritty or rough.
Reconstituted gems fit into a separate category.
Although reconstituted gems do contain genuine material, experts regard them as imitation. Reconstituting, or reconstructing, means that small fragments of gem material have been combined to form a large piece. Amber and turquoise are two common examples. Reconstituted amber, typically called ambroid or pressed amber, is made from scraps and shavings generated by amber carvers. The tiny pieces are collected and heated, then pressed into large blocks.