Clay is a type of fine-grained natural soil material that contains specific clay minerals. While most pure clay minerals are characterized by white or light colors, natural clays frequently exhibit a wide variety of different hues due to the presence of impurities.
One notable characteristic of these materials is their coloration; for instance, small amounts of iron oxide can cause natural clays to appear reddish or brownish. Although the provided subject mentions a city by this name in the United States, the primary definition refers to the geological soil material.