After a final polish, the stone is mounted in precious metal.

A "Brillianteer" then adds a further 24 facets girdle and 16 below.

More facets are put on in groups and in sequence - the star facets & upper girdle on the crown & lower girdle facets & the culet on the pavilion.

The central facet the flat table is ground first, then the bezel facets.

The top is cut off, and the stone rounded on a lathe by another diamond.

A round diamond crystal is selected for faceting.

                          

   4. Top & bottom                        5. Finishing                             6. Mounting

                          

         1. Rough                                    2.Cut                                      3. Grind

There are several stages in the cutting of a gemstone, each of which may be carried out by a different expert. In our example, a rough diamond crystal is fashioned into a brilliant-cut. This is the most popular cut for this stone because it maximizes the gem's naturally strong light dispersion. However because each stone is a different shape, or has imperfections within it, or because retaining the weight is of paramount importance, the cut in its ideal form (the "make") may not be possible. Nevertheless, the essential aim is to make the diamond bright and "sparkling", showing flashes of colour called fire. To this end, the size, number, and angles of the facets are mathematically calculated. The rough crystal is sawn or cleaved to obtain a basic workable piece, then turned on a lathe against another diamond to give it a round shape. The facets are then cut and polished in stages, and the stone is given a final polish before mounting.

FACETING

The most usual method of fashioning a gem is to cut the surface into a number of flat faces, known as facets. This gives the stone its final shape, or "cut". The craftsman, or lapidary, who cuts the stone aims to show its best features, taking into account its colour, clarity, and weight. He may, however, have to compromise to retain weight and therefore value.