From ancient times until the 1600’s little was attempted in the way of shaping gemstones other than to smooth or polish the natural form. Although similarly smoothed, or _tumbled_, gemstones recently have returned to fashion, the finest pieces of gem rough are now converted mainly into _faceted_, or shaped, stones. Standard types of facets—the flat faces that are ground and polished on the rough gem material—have been given individual and group names. A typical example is the _brilliant_ cut, which is most commonly used to best bring out the qualities of a diamond. [Illustration: The standard brilliant cut, with a pattern of many facets, is commonly used for gemstones having a high refractive index and, therefore, great brilliance.] [Illustration: Characteristic of the standard brilliant cut are the 32 crown facets surrounding a relatively small, flat, table facet and the 24 pavilion facets and culet at the bottom of the stone.] [Illustration: Ideal proportions for the standard brilliant cut have been carefully determined so that the maximum amount of light will be reflected back out the top of the stone. Incorrect proportions cause the light to be lost at the bottom of the stone.] [Illustration: The step cut, often called the emerald cut, frequently is used for colored stones because the large table permits a good view of the color.] [Illustration: The emerald or step cut provides a large table and a full bottom for the stone. Although the number of crown and pavilion facets may vary, the general pattern is maintained.] [Illustration: The simplified English brilliant cut takes maximum advantage of the strong dispersion of diamond, with its flashes of fire, but the fewer facets provide less sparkle than the standard brilliant cut.] The diagram shows a brilliant-cut diamond with angles and facets arranged to give the stone maximum internal reflection as well as to make use of its strong dispersive ability. Certain of the light beams passing into a brilliant-cut diamond produce colorless brilliance by being reflected back out of the stone through the _table_ by which they entered. Other light beams, emerging through inclined facets, are split up by dispersion into the rainbow, or fire, effect so prized in diamonds. A stone that has been cut too wide for its depth, with incorrect facet angles, will look large for its weight but its brilliance and fire will have been drastically reduced. [Illustration: The English brilliant cut has 28 crown and pavilion facets—28 fewer than the standard brilliant cut.] [Illustration: The Dutch rose cut is a very simple one that is used mainly for small diamonds in jewelry that features a larger, colored stone. It is based on a form that originated in India and was introduced through Venice.]