MAGICAL JEWELLERY : Any jewelry worn for a magical purpose.

MAGMA : Rock in a molten state below the Earth's surface. See also Lava.

MAN'S SHIRT BROOCH : A brooch worn by a man in place of a tie, at the base of the neck.
MASK : An ornament worn to conceal one's identity.

MASSIVE : Used to describe minerals that have an indefinite shape, or that consist of small crystals in masses.

MATRIX : The rock in which a gem is found.

MEDAL : A metal ornament bearing a design on the front, and often on the back as well, usually disclike in shape, but also in other forms. Worn as a charm; ornament ; conferred as a symbolic reward for services or achievement ; or in remembrance of a notable event. It may also include an inscription. Some are worn as a pendent, others at the waist, on the breast, or suspended by a ribbon. Within this category are also orders of honor and merit issued by governments and societies.

MEDALLION : A large medal., tablet, or panel often issued for a memorial purpose. The front and sometimes also the back are decorated, may contain a portrait, figures, or other subject molded in relief. The term is also generalized to mean any large, round, decorative shape used in a design, as in jewel, a rug, etc.

MEMORIAL JEWELLERY : Jewelry meant to commemorate an occasion, event, or an individual. 

METAL MESH : A pattern made from thin wires.

METAMORPHIC ROCKS : Rocks that have been changed by heat and/or pressure to form new rocks consisting of new minerals.

MINERALS : Inorganic, naturally occurring materials with a constant chemical composition and regular internal atomic structure.

MIXED-CUT : Cut in which the facets above and below the girdle are styled in different ways-usually brilliant-cut above and step-cut below.

MOHS' SCALE OF HARDNESS : Measure to other mineral's, based on its ablitiy to resist scratching.

MOKUME-GANE : Laminated metals that have been fused or brazed together like a sandwich, and passed through a flat or wire-forming rolling mill to make the material easier to fabricate or raise. The sandwich or "billet" can also be forged without the use of the rolling mill. Patterns are then punched, filed, and hammered to produce a desired pattern.

MOUNTING : The process by which precious or non precious-stones are secured.