Explanation:

Beryllium is a well-known element in the gem world, since it is an essential constituent of many gemstones, including emerald, beryl, aquamarine and chrysoberyl.
The topic is very important because  Beryllium treatment (Be heat) is a recent addition to techniques for treating gemstones. Beryllium treatment is a form of heat treatment, mainly for sapphire, that adds the element beryllium to the heating process.