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M Edit 20 terms found

M
A grade in GIA’s Color Grading System…. at the end of the “Faint Yellow” category.
Main Facets
The 8 crown and the 8 pavilion facets of a Brilliant Cut diamond. These are the facets where the angles are measured in order to determine a diamonds proportions.
Mainspring
The principal spring of a watch that supplies the force of motion to the gear trains.
Make
A trade term referring to the proportions, symmetry, and polish of a diamond. Commonly stated as a “good make”, “well made”, a “poor make”, etc.
Marquise
The marquise shape is an elongated oval with points on both ends. Said to be named after the Marquise de Pompadour, the mistress of King Louis XV.
Marquise Cut Diamond
A Fancy Shape diamond which is “boat shaped”, elongated with points at each end. The term “Marquise” came from a story about the origins of the shape. The French “le Roi Soleil”, Louis XIV wanted a diamond to be polished into the shape of the mouth of the Marquise of Pompadour.
Master Stones
A set of diamonds of known color that are used to decide the body color of other diamonds that are compared to this set of master diamonds. A set of master stones must have very exacting specifications in order to be used.
Mechanical
Movement used on traditional timepieces, whereas the watch uses a main spring for its power source and must be hand wound.
Melee
A French word meaning confused mass. A trade term that is used to describe small diamonds. They are usually side diamonds or accent diamonds in a piece of jewelry.
Mercedes Hands
Nickname used to describe a style of hands used on some sports model watches. The name comes from the hour hand which features a round emblem which resembles the logo of the German automobile manufacturer Mercedes Benz. Rolex refers to these hands as skelette or skeleton hands.
Metallic (luster)
One of the technical terms used to refer to the luster of a gemstone. A gemstone that is reflective like polished metal is said to have a metallic luster. Hematite is one of the rare examples.
Micro-Stella
Tiny screws used for adjustment of the balance.
Mid-sized Watches
Refers to Rolex models that are 80% of the size of a standard men’s watch.
Milled Edge
Having a grooved or coined edge. First used on watch cases by the Dennison Watch Case Company in the early 1900s, and is still featured on the back of all Rolex Oyster cases.
Mixed Cut
This faceting style has both step-cut (crown, top) and brilliant-cut (pavilion, bottom) facets.
Mohs Scale
In 1812, a scale of mineral hardness was devised by the German mineralogist Friedrich Mohs, who selected the ten minerals because they were common or readily available. The scale is not a linear scale, but somewhat arbitrary. The scale of mineral hardness characterizes the scratch resistance of various minerals through the ability of a harder material to scratch a softer material.
Moissanite
A lab-created diamond simulant based on the structure of natural moissanite. On Mohs’ scale of hardness, moissanite is 9.5. It has more brilliance, fire and luster than any hard jewel on earth, including diamond.
Moon Phase
A type of dial showing the changes in the moon’s phases, or lunar cycles.
Mounting
Trade term for a piece of jewelry in which a gem or other object is set.
Movement
The machinery of any time piece.