In North Carolina you may fing it difficult to find. It is mostly marketed in th North East. If it isn't in you local HD, you might try finding a store number in the NE that has some in stock and try arranging a store to store transfer. If this isn't possible, www.purearagonite.com
is a slightly more expensive second choice. You should also make sure you look for the Southdown marketed under YardRight Tropical playsand. It will be speciofically marked, "Not Safe For Aquariums", it is safe, they just do this for liability.