Which one of the following gemstones contains beryllium metal?

Emerald is a precious gemstone and a variety of the mineral beryl, which is chemically defined as beryllium aluminum silicate with the formula Be3Al2(SiO3)6 [1]. Beryl is the primary industrial source of the light metal beryllium [1]. While pure beryl is colorless (goshenite), the presence of trace elements like chromium or vanadium gives emerald its characteristic deep green hue. Other varieties of beryl include aquamarine (blue) and morganite (pink) [1]. In contrast, ruby and blue sapphire are varieties of the mineral corundum, which is composed of aluminum oxide (Al2O3) and does not contain beryllium. Topaz is an aluminum silicate containing fluorine and hydroxyl groups, also lacking beryllium. Therefore, among the given options, only emerald contains the metal beryllium as a fundamental constituent of its crystal lattice.

Sources

1. [1] https://www.britannica.com/science/beryl