On June 28, 1973, the General Assembly designated the emerald as the state’s official precious stone.
Emeralds are a variety of the mineral beryl. Beryl is colorless in its pure state, but chromium turns beryl green. The aquamarine is blue beryl, and there are also yellow, light green, red and pink varieties. Beryl, in all its variety of colors, is found among mica, quartz and feldspar, all of which are abundant in the North Carolina mountains.
North Carolina is very rich in minerals. More than 300 varieties have been found—more than in any other state. North Carolina also has the largest emerald deposits found in the United States. Most of the mining operations for the gem are in Alexander and Mitchell Counties.
In 2012, the Nature Research Center at the North Carolina Museum of Natural Sciences acquired four of the largest emeralds ever found in North America. Surprisingly, all four of the gems were found on the same property and three were found on the same day. One of the stones, known as the Carolina Emperor, is a whopping 64 carats.
Check out NCpedia for more on the emerald and other state symbols.