Page:A treatise on diamonds and precious stones including their history Natural and commercial.djvu/41

, when well set, always appear larger than when they are loose, and this circumstance gives great advantage to the seller. Shallow brilliants, that have a great surface, are for this reason always in request, and are generally set close. Thus a stone of only a carat may appear as large as a well-proportioned stone of six grains,

smallest flaw, or foul, (as it is called) greatly diminishes the price of the diamond; and if it be tinged with yellow, brown, &c. a fault characterized by the technical term off color, its value falls very considerably, and is frequently reduced from a third to one half. To counteract these defects, and to conceal the appearance of what are deemed imperfec-