Diamond Cut

A diamond cut is a style or design guide used when shaping a diamond for polishing such as the brilliant cut.The most popular of diamond cuts is the modern round brilliant, whose facet arrangements and proportions have be perfected by both mathematical and empirical analysis. Also popular are the fancy cuts which come in a variety of shapes a lot of of which were derived from the round brilliant. A diamond's cut is evaluate by trained graders, with higher grades given to stones whose symmetry and proportions mainly closely match the particular "ideal" used as a benchmark. The strictest standards are useful to the round brilliant although its facet count is invariable, its proportions are not.

Fancy cuts

Even with modern techniques, the cutting and polishing of a diamond crystal always results in a dramatic loss of weight; rarely is it less than 50%. The round brilliant cut is preferred when the crystal is an octahedron, as often two stones may be cut from one such crystal.Oddly shaped crystals such as macles are additional likely to be cut in a fancy cut (that is, a cut other than the round brilliant) which the exacting crystal shape lends itself to. The prevalence and choice of a particular fancy cut is also influenced by fashion normally speaking, these cuts are not held to the same strict standards as Tolkowsky-derived round brilliants Most fancy cuts can be grouped into four categories: modified brilliants, step cuts, mixed cuts, and rose cuts.

Modified brilliants

This is the most populous category of fancy cut, because the standard round brilliant can be effectively modified into a wide range of shapes. Because their facet counts and facet arrangements are the same, modified brilliants also look (in terms of brilliance and fire interplay) the most like round brilliants and are therefore (in general and at present) the most saleable.Modified brilliants include the marquise or navette (French for "little boat", because it resembles the hull of a sailboat), heart, triangular trillion (also trillian or trilliant), oval, and the pear or drop cuts. These are the most commonly encountered modified brilliants.

Step cuts

Stones whose outlines are either square or rectangular and whose facets are rectilinear and arranged parallel to the girdle are known as step- or trap-cut stones. These stones often have their corners truncated, creating an emerald cut (after its most common application to emerald gemstone) with an octagonal outline. This is done because sharp corners are points of weakness where a diamond may cleave or fracture. Instead of a culet, step-cut stones have a keel running the length of the pavilion terminus. The advantage of the step cut is that it conserve more of the weight of the raw diamond than the brilliant cut. One of the mainly popular examples of the step cut is the emerald cut. The emerald cut has the long faceted planes of the step cut, but has cut corners, which helps to keep away from chipping or cleaving of the edges. The culet is not present in step cut stones, but rather they have a keel that extends along the length of the end or bottom of the pavilion. Step cut stones accomplish not have the fire or flash of brilliant cut diamonds, but do exhibit brilliance and scintillation as the light move clearly among the mirror-like facets. Due to the nature of the long facets, step cut stones should have tremendous clarity, as any flaws can be easily noticed. This means so as to step cuts have a high luster, and a warm glow. Triangle, obus and kite cuts are also integrated in the step cut category.

Mixed cuts

Mixed cuts share aspects of both (modified) brilliant and step cuts: they are meant to combine the weight preservation and dimensions of step cuts with the optical effects of brilliants. Typically the crown is brilliant cut and the pavilion step-cut. Mixed cuts are all relatively new, with the oldest dating back to the 1960s. They have been extremely successful commercially and continue to gain popularity, loosening the foothold of the de facto standard round brilliant. The most successful mixed cut is the Princess cut. The intended effect is to offer the brilliant finish of the brilliant cut, even as preserving the weight retention of the step cuts. The extremely popular Princess cut is the mainly well known of the mixed cuts, and has grown popular enough to warrant its own grading system with mainly gemological laboratories.

Rose cuts

Various forms of the rose cut have been in use since the mid 16th century. Like the step cuts, they were derived from older types of cuts (see History section). The basic rose cut has a flat base (no pavilion) and a crown composed of triangular facets (usually 12 or 24) in symmetrical arrangement, which rise to form a point. They are usually circular in outline; variations include: the briolette (oval); Antwerp rose (hexagonal); and double Dutch rose (resembling two rose cuts united back-to-back). Developed prior to the make use of of electric lighting, rose cuts fell out of favor in the early 20th century, due to their lack of brilliance. They are seeing a renewed rise in status as the market for older, antique jewelry makes the use of the rounded rose cut type stones additional desirable.Rose cuts are seldom seen nowadays, except in antique jewelry. Like the older style brilliants and step cuts, there is a growing demand for rose cuts for the purpose of repairing or reproducing antique pieces. The rose cut is still routinely used for melée diamonds.

Cut grading

The "Cut" of the "4-Cs" is the mainly difficult part for a consumer to judge when selecting a good diamond. This is because some certificates will not show the important capacity influence cut (such as the pavilion angle and crown angle) and will not provide a subjective ranking of how good the cut was. The other 3-Cs can be ranked just by the rating in each category. It require a trained eye to judge the quality of a diamond cut, and the task is difficult by the fact that different standards are used in different countries.