Coral Precious coral or red coral is the common name given to Corallium rubrum and several related species of marine coral. The distinguishing characteristic of precious corals is their durable and intensely colored red or pink skeleton, which is used for making jewelry. Red corals grow on rocky sea bottoms with low sedimentation, typically in dark environments—either in the depths or in dark caverns or crevices.
Resin is a "solid or highly viscous substance," which are typically convertible into polymers. Such viscous substances can be plant-derived or synthetic in origin. They are often mixtures of organic compounds. It is durable and transparent, and starts as a liquid form. After casting, it becomes solid and resilient. Special resin molds with smooth surfaces are created to give it a glossy finish.