Older diamonds can be replaced or re-cut to modern proportions, but replacing or re-cutting stones mounted in antique or period pieces could adversely affect the value of the jewelry. That common sense, and it is common sense whether or not the jewelry is insured, and whether or not it is valuable. The precautions you should take with any jewelry that you like and that means anything to you, in fact, are simple common sense.
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 Diamonds of G color are nearly colorless. G color diamonds may have a slight yellowish tint when viewed against white flat background. When set in platinum or white gold jewelry the presence of color will not be noticeable which makes diamonds in this color grade very popular.
Clarity Inclusions and external blemishes in diamonds of SI1 clarity may be easy to spot under 10X power magnification. Location of the inclusions greatly affect their visibility to the naked eye. SI1 diamonds of good color produce as good of a sparkle as the more expansive VS graded stones of lower color. Excellent bargains may be fond in this category.