GLOSSARY OF DIAMOND TERMS

September 16, 2016

Making the diamond claddagh ring is our passion. Here are some interesting terms relating the diamond which you may not have come across before.

HEART SHAPE: - A style of cutting which represents a variation of the pear shape widely used in our diamond claddagh ring.
KIMBERLITE: - Another name for 'blue ground' ; derived from Kimberley.
LAMPROITE: - Volcanic rock, occasionally containing diamonds, found in the deposits in Western Australia. It is the only known diomondiferous rock with a subsidiary mineral content and chemistry different from that of kimberlite.
LILAC-PINT: - A very rare kind of 'fancy-colour'. Such diamonds have come mainly from Brazil and, more recently from Australia.
MACCLE: - A rough diamond consisting of twinned crystals, generally triangular in shape and often flattish. The side is marked by a curious fishbone pattern with the grain going in one direction on the top and in another on the bottom.
MANGELIN: - An old Hindu weight for gems, equal to approximately 1.4 metric carats.
MARQUISE: - A style of cutting in which the outline of the girdle is shaped like a boat.
MELEE: - (a) Small unbroken octahedral diamonds weighing less than 1.0 carat. (b) A selection of small polished brilliant-cut gems weighing up to 0.20 carat.
MOGUL CUT: - An ancient style of cutting, principally from cleavages, employed in India. The result was a somewhat bulky gem with a broad, often asymmetrical base, an upper part, consisting of usually four shallow facets or a table, plus two or more areas of strip facets parallel to the base and oriented vertically.
NAVETTE: - Another word for a marquise; derived from the Latin (navis - boat).
OCTAHEDRON: - The classic shape of a rough diamond. It has eight equilateral, triangular faces, each of which intersects all three of the crystallographic axes at an equal distance from the centre.
OLD-MINE CUT: - An early form of the brilliant-cut; as opposed to being circular, the girdle has an almost square or cushion-shaped contour.
OVAL CUT: - Also called the 'oval-brilliant' cut; a style of cutting in which the girdle is a rounded oblong in outline.
OZIDIZATION: - A species of impurity found in some rough diamonds. The presence of iron ozide within the cracks in a stone imparts an orange or reddish-brown colour which, after removal, may leave a gem of a fine colour. Occasionally it may remain in a polished gem (e.g. the 'Pigot' diamond).
PAVE-SET: - A style of setting in which small diamonds are set as close together as possible thereby showing the least amount of metal.
PAVILION: - The lower half of a faceted gemstone lying below the girdle.
PEAR SHAPE: - A style of cutting in which the girdle has the outline of a pear; it represents a variation of the brilliant cut and may possess the same number of facets.
PENDELOQUE: - Similar to the pear-shape in outline but with the narrower end longer and more pointed.
PICKING TABLE: - A flat or slightly sloping platform on which diamondiferous ore is seperated from other material. Small operations still employ the device; elsewhere it has been superseded by the grease table.
PIPE: - The primary source of diamond: a conically-shaped extrusion of volcanic rock (blue ground) which may or may not contain diamonds.
PIT: - A kind of indentation found on the surface of a rough diamond.
PORTRAIT STONE: - A thin polished diamond, cut from a flat, that enables one to see through to any object over which it has been placed.

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