Emerald is most often found with some visible inclusions. It is rarely eye-clean in sizes above one carat. Because of this, a greater degree of tolerance should be exercised when judging the clarity of emerald. More attention should be paid to diaphaneity than to strict flawlessness. The finest emeralds exhibit a wonderful clear crystal that gives the stone a marvellous inner glow. If the stone has this trait, a few visible inclusions – what experts call “jardin” (garden) – are easily forgiven. Such stones are more highly valued than those which are strictly flawless but lack the limpid quality of good crystal. Most aficionados prefer emeralds cut in the traditional step or emerald cut. This cut has seventeen long, narrow, step like facets. A majority of emeralds are cut in this style, both because it accentuates the warm satiny hue of the gem and, by happy coincidence, it is usually the most efficient use of the rough material.
Experts describe emerald’s brilliance as “satiny like the lustre of a satin ribbon. Emerald has a softness which contrasts with the “crisp” brilliance of tsavorite garnet, its only rival for the title of “greatest of the green.” This is partly a function of emerald’s relatively low (1.57-158) refractive index and partly a result of cutting style. A slightly bluish green emerald with excellent crystal appears to glow with an appealing richness and warmth that is alien to tsavorite.~Emerald is soft where tsavorite is hard. To fully understand this quality the budding connoisseur must educate his eye by comparing a large number of emeralds.