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Upper Girdle Facet Height
With upper girdle facets too low, the kite shapes are odd in appearance and create elongated star facets. The proper height is in red.
Upper girdle facets should be slightly more than 50% in height for the proper kite shape appearance.
The upper girdle facets (the facets forming the lower section of the kite shapes on the crown) can also be a problem if not polished into correct shapes. The idea of the upper girdle facets is again, to provide many additional angles to send light in a combination of many different directions. By the same token, these facets must be polished in a shape that is pleasing under 10x. The configuration of the perfect kite shapes is part of the very important symmetry that you will get used to recognizing. On a full crown (e.g. 58% table, 34 ° angles), the upper girdle facets will generally be polished to a height of just over 50% (of girdle to table) to achieve the proper kite shapes. This also helps the stars (eight triangular facets edging the table) to fall into their ideal equilateral, triangular shapes. The thinner the crown, the shorter the stars will have to be, in order to achieve an attractive kite shape, and the fuller the crown (fuller than acceptable standards), the longer the stars will have to be.
