culet

• The stone is then reversed and 24 facets, and the culet, polished on the back. —  A Text-Book of Precious Stones for Jewelers and the Gem-Loving Public
• If the basal lines of these cross facets, where they join the sides of the skill facets, are extended to the peak, or narrow end of the stone, these lines, together with the sides of the cross facets, will form four five-sided facets, called the "pavilions"; the spaces between these four pavilions have their ends nearest the girdle formed by the inner sides of the skill facets, and of these spaces, there will, of course, be four, which also are five-sided figures, and are called "quoins," so that there are eight five-sided facets -- four large and four narrow -- their bases forming a square, with a small portion of each corner cut away; the bases of the broader pavilions form the four sides, whilst the bases of the four narrower quoins cut off the corners of the square, and this flat portion, bounded by the eight bases, is called the "culet," but more commonly "collet." —  The Chemistry, Properties and Tests of Precious Stones
• However, one must use much judgment in such a case, as sapphires, like other corundum gems, frequently have their color irregularly distributed, and the skillful lapidary will place the culet of the stone in a bit of good color, and thus make the whole stone appear to better advantage. —  A Text-Book of Precious Stones for Jewelers and the Gem-Loving Public
• Such well made brilliants when held up to a bright light appear almost black -- that is, they fail to pass any of the light through them (except through the tiny culet, which, being parallel to the table above, passes light that comes straight down to it). —  A Text-Book of Precious Stones for Jewelers and the Gem-Loving Public
• The truncating of the lower cone forms the tiny facet known as the culet, which lies opposite to the table and is parallel to the latter [see B, Fig. 13, cut —  A Text-Book of Precious Stones for Jewelers and the Gem-Loving Public

Allen's Synonyms and Antonyms