Page:A treatise on diamonds and precious stones including their history Natural and commercial.djvu/115

 teen parts. Five-eighteenths are cut away to form the table, and one-eighteenth for the collet, which will reduce the height one-third, and the diameter of the collet will be one-fifth of the table. If these distances are preserved, the collet will play in the centre of every facet; but if there be any variation, it will play higher or lower, and greatly diminish the intensity of lustre. The corners are truncated, to correspond with the table; the bizel is formed by eight lozenges and twenty-four triangles, and the collet-side by four large irregular pentagons, and four lozenges, radiating from the collet as a centre, and bordered by sixteen triangles at the girdle; thus making, in the whole, fifty-six facets. The triangles on the bizel, adjacent to the girdle, are called skill facets, and those which join the table, star facets; those upon the collet-side