The layout of the diamond's facets and their relation and proportion to one another comprise the mass of the diamond and reveal its symmetry. Precise angles and crisply struck, well-placed facets will result in fine symmetry.

The importance of better symmetry is revealed in the diamond's reflection on light. The better the symmetry, the better the reflection. The line drawings that follow point out this fact.

The Round Brilliant shape provides good illustration of proper symmetry -- or the lack of it. The first figure depicts the parts of the shape, each interior line revealing the presence of a facet:

Well-made diamonds are cut so that light entering the diamond, shown here by arrows, is reflected by the facets back through the top of the diamond to the human eye. The properly proportioned assemblage of facets shown in Figure 2. maximizes the diamond's brilliant sparkle and fiery spectrum of color.

Some diamonds are cut so as to maximize their carat weight. This may create a gemstone too deep in proportion to its mass. As shown in Figure 3., such a circumstance allows light to pass through the diamond's bottom facets. The result: a dark, lifeless stone.

Sometimes diamonds are cut to appear larger, where the cutter has emphasized the face-up spread of the gemstone. This may often lead to shallow-mass diamond illustrated in Figure 4. Lacking the proper proportions, this type of stone also loses light through its bottom facets and the diamond appears glassy and dark.