Be sure to look for these factors on the diamond certificate. Some jewelers may specialize in certain types of jewelry. New York City GIA says certification is important for emeralds, rubies, and sapphires.
Diamond Certificate
Explanation of Cut, Color and Clarity of This Diamond
Cut Quality The ideal cut diamond is a very precise mathematical equation, where diamond proportions and angles are cut to optimize the diamond's superlative optical properties, in particular it's high refractive index and color dispersion, to create a diamond of unequaled beauty with perfect balance of brilliance and fire. In layman's terms, the diamond is cut to make it the most beautiful diamond so it retains its intrinsic value.
Color E color diamonds are virtually colorless. E color grade is very rare. The naked eye will not detect any presence of color. E color grade is indistinguishable from D without instrumentation.
Clarity Diamonds of SI1 clarity are slightly included grade one. Inclusions in SI1 diamonds are easily identified through a strong loupe. Finding flaws in this category with the naked eye is difficult. The diamonds in this category maintain their integrity, depending on the location of the inclusions.