North Carolina designated granite ("the noble rock") as the official state rock in 1979. High quality North Carolina granite is used as a building material for both industrial and laboratory applications where super-smooth surfaces are required.

North Carolina has an abundance of granite. When Robert Gilmer found the “big white rock” on his newly purchased farm in Surry County in 1849, he was so angry that he insisted the seller reimburse part of his money.

“The Rock” (as it’s known locally) became one of the first commercial natural stone businesses in North Carolina and is now Mount Airy White Granite Quarry, the largest open-face granite quarry in the world (astronauts circling the earth can see it from space). Granite from this quarry is gleaming, unblemished, and without seams to mar its splendor.

Source:

State Rock - Granite: North Carolina State Library
NC Granite in Mount Airy: www.ncgranite.com

Links:

Geological Symbols - 50 States List