Gumbo clay
Revision as of 07:05, 24 July 2013 by (username removed)
Description
A sticky, highly plastic clay that dries to form a hard, tough nonporous matrix. Gumbo clay is commonly found in the southern and western United States. The fine silty soil is mainly used for railroad ballast. For other uses, grog or sand is added to the gumbo clay minimize shrinkage on baking.