The General Assembly of 1973 designated the emerald as the official State Precious Stone. (Session Laws, 1973, c. 136).
A greater variety of minerals, more than 300, have been found in North Carolina than in any other state.
These minerals include some of the most valuable and unique gems in the world. An emerald crystal weighing 1869 carats, thought to be the largest ever found in North America, was unearthed in late 2003 at a mine in Hiddenite, near Statesville. A 71-carat stone found on the same property yielded two finished stones--the 7.85 carat Carolina Prince that sold for $500,000, and the Carolina Queen (18.88 carats).
Session Laws, 1973, c. 136
H. B. 82 CHAPTER 136
AN ACT TO DESIGNATE THE EMERALD THE PRECIOUS STONE OF THE STATE.
The General Assembly of North Carolina enacts:
Section 1. Chapter 145 of the North Carolina General Statutes is amended by adding the following section thereto:
"§ 145-8. The Emerald is hereby adopted as the official State precious stone of the State of North Carolina."
Sec. 2. This act shall become effective upon the opening of the National Gem Show in Charlotte June 28, 1973.
In the General Assembly read three times and ratified, this the 5th day of April, 1973.
References and additional resources:
The Mineral Industry of North Carolina 2003  (from U.S. Geological Survey) -- mentions several emeralds from North Carolina
The Mineral Industry of North Carolina 2006  (from U.S. Geological Survey) -- latest available report
North Carolina Emeralds  (commercial site)
Resources in Worldcat 
1 June 2007 | Anonymous