Zircon (Imitation)

For one thing, most raw diamonds cannot be cut for use as jewelry-quality diamonds, much less be cut to ideal cut ratios. Out of the few raw diamonds found that can be utilized for jewelry, only a small percentage of these have the physical properties to be cut to the ideal cut round brilliant proportions. This is not to say that they are the most rare of diamonds, as they are not, but simply to note that due to such variables as naturally occurring inclusions (flaws within the diamond's crystalline structure, such as spots of other minerals, and cleavage lines) it is impractical, if not impossible, to cut all jewelry quality raw diamonds into ideal cut round brilliant diamonds.