If she like big one, go for a diamond with big carat weight but with poorer quality in terms of color, cut or clarity. Also some good choices are personalized doorplates, a map of the sky on the wedding night, wedding portrait platters, a bottle of wine as old as their marriage or a tree seeded in the wedding day. As a final conclusion, you have to keep in mind the fact that a wedding anniversary gift must be something unique and personalized in order to express your feeling better.
Diamond Certificate
Explanation of Cut, Color and Clarity of This Diamond
Cut Quality Good cut diamonds reflects most light that enters the diamond, but not as must as a premium cuts. They are less expensive than the premium-cut. Roughly 25% of diamonds are good-cut based on cut quality. This grade represents an excellent balance between quality and price.
Color K color is the first letter in faint yellow category. K color diamonds set in yellow gold settings look just fine. Go for a strong diamond fluorescence. It will compensate yellowish color effects. One may want to sacrifice diamond color for the sake of bigger size. K color diamonds are just perfect for that.
Clarity VS1 diamonds have very small inclusions. Usually an experienced grader does not find any internal faults, but does not have great difficulties to see the inclusions when he moves the diamond a little from side to side. Typical inclusions of this group are small, light clouds or small light cracks on the girdle.