Mabe Pearl - an assembled cultured blister pearl consisting of a dome of mother-of-pearl cemented over a plastic or glass dome.
Make - a jewelry trade term referring to the quality of a gemstone's cut.
Maker's Mark - a manufacturer's stamp, usually consisting of a symbol, initials or the name of the company stamped on a piece of jewelry.
Marquise Cut - a boat or football shape gemstone with pointed ends.
Melee (rhymes with belly) - refers to small diamonds under 0.20 carats.
Millegrain - a style of decoration that forms a minute string of adjacent beads of raised metal which often surrounds a gemstone or the edges of a piece of jewelry.
Mixed Cut - a gemstone cut in which the crown or upper part of the gemstone is brilliant cut and the pavilion or lower part of the gemstone has a step or trap cut.
Mounting - the metal framework in which gemstones are set in various articles of jewelry.