Loose Diamond Definitions: D

De Beers-This company is the major factor in the diamond industry, because it holds a controlling interest in a number of diamond-mining companies and in companies having buying contracts with independent producers.

Depth Percentage-The depth of a stone measured from the table to the culet, expressed as a percentage of the stone’s diameter at the girdle, is a relationship used in the analysis of the proportions of a fashioned diamond.

Diamond-A mineral composed essentially of carbon that crystallizes in the "cubic," or "isometric," crystal system and is therefore singly refractive. IT is by far the hardest of all known natural substances; only manmade Borazon and synthetic diamond are as hard.

Diamond Certificate-A certificate awarded to those who complete successfully the "Diamond Course" of the Gemological Institute of America, which requires passing the diamond-grading and diamond-appraising instruction and practice.

Diamond Cut-A name sometimes used in the colored-stone trade for brilliant cut.

Diamond Saw-A saw used for dividing or separating diamonds.

Discount Diamonds-the lowering of the price on a diamond below retail price.

Dispersion-The property of transparent gemstones to separate white light into the colors of the spectrum.

Dodecahedron-One of the seven basic forms in the highest symmetry class of the cubic, or isometric, crystal system.

Draw Color-When several diamonds are placed together in a diamond paper and light passes through one stone after another, each stone tends to intensify the slight color of the other.

Durability-The durability of a gem depends both on its hardness and toughness.

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