Look to see that the diamond stud is clear, with no obvious inclusions. The base metal will show through jewelry that is thinly electroplated. Most better gold jewelry is cast with lost wax method, which leaves no casting marks.
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 Slight presence of color may be detected in F color graded diamonds by an expert gemologist. The diamonds of this grade are considered colorless. Great choice for the purist. Look for a fluorescence rating of faint, inert, none, or negligible.
Clarity Diamonds of I1 clarity are included. Typically inclusions in I1 diamonds can be seen with the naked eye through the crown side of the diamond. Although visible usually such inclusions only slightly affect the brilliancy of the diamond. I1 clarity diamonds may be a good choice for budget conscious customers.