Enamel - a glassy coating, fused with heat to the surface of a piece of jewelry. Also used on glass and pottery.
End Cap - a tube, coil, or hoop placed over the end of a necklace, chain or bracelet. The clasp from the opposing end of the item hooks onto it to secure it the neck or wrist.
Eternity Ring - a ring that contains facetted gemstones, such as diamonds, set edge to edge around the entire ring.