The collection and transformation of these valuable natural pearls into jewelry makes for a small cottage industry in the state. Although organic and not, by strict definition, minerals, they are included because they are an important Wisconsin lapidary material. Pearls are found in clams in various streams and lakes in the county. Pearl-bearing clams occur in water bodies throughout the county. Pearls occur in clams from the Mississippi River near Stockholm and elsewhere along the Mississippi River corridor in Pepin and adjacent Pierce and Buffalo Counties.
Pearls occur in clams in the Rock River.