There are numerous online diamond retailers selling certified diamonds. If you need it 1/2 size larger, then send the ring you purchased back to jeweler for an exchange. It consists of a metal ring, which might be fitted with precious stones.
Explanation of Cut, Color and Clarity of This Diamond
Cut Quality Diamonds of premium cut proportions are almost as good as ideal. Most people will not be able to distinguish an idea cut from premium. Less diamond material is lost in the process of cutting the diamonds making it less expansive. One needs to keep in mind that appearance of a diamond is very subjective and cannot be fully evaluated just by their proportions along.
Color Diamonds of F color are very close to colorless. Very small percentage of natural diamonds fall into this category. Even a trained professional will not be able to detect presence of color 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.