1. . 
A lignite that has been treated (admixed or reacted with) chromic or chromate salt, such as potassium or sodium chromate or dichromate or chromic chloride. Also, chrome lignite may contain added (sometimes reacted) KOH or NaOH. Chromed mud additives have largely been eliminated from usage in the US because of environmental concerns. Chrome lignite was more temperature-stable than plain lignite in clay-based water muds.