A quahog is a bivalve clam native to the eastern seaboard of the United States. Used mostly as a food source, these clams occasionally produce a pearl-like gem (non-nacreous calcareous concretion) in a beautiful natural purple color. Used as “wampum” by Native Americans in that region, they are still valued today. Not many of these concretions are produced, approximately 1 in 100,000 clams produce a “pearl”, and of those, very few are gem quality.