World population has been expanding rapidly, and it is only in 2100 when the increase in the world population is stadilized. By 2100, the world population is estimated to be 12 billions, which is three times of the present population. In contrast, the production of mineral resources, especially of gemstones, is expected to decline in future. This has already appeared on the decline of world production of natural diamonds of gem quality. Statistics indicate that the production of gem diamonds has been declining since 1970. Under these circumstances, it is expected that the concept of gemstones is forced to be modified, and the standard in evaluating gem quality will have to be moderated in near future. In evaluating quality of gem diamonds, the most important factor to create divergence in the evaluation is clarity of stones. It is therefore important to carry out serious studies on inclusions in diamonds.
