Emerald

An emerald is a bright green gemstone created by the tinting of beryl with chromic oxide.

By the 23rd century, the synthesis of emeralds was easy enough, and the results high quality enough, that the stones had lost most of their value. Emeralds were among the gemstones offered as a bribe by Korob, who was attempting to test the character of Kirk, Spock, and McCoy. (TOS: "Catspaw")

An emerald tie-pin was presented to Sherlock Holmes by Queen Victoria after he solved the theft of the Bruce-Partington plans. (TNG: "Elementary, Dear Data")

The Zaterl Emerald was a type of emerald purported to exist in the ruins of Ligillium. (TNG: "Devil's Due")