. "Sapropelic-lignite - A type of coal. It is a member of the sapropelic coal series. The members of the sapropelic coal series can be ranked in order as sapropel (the unlithified form), sapropelic-lignite, and sapropelic-coal (the lithified forms) based on increasing carbon content and decreasing volatile content. Sapropelic-lignite is macroscopically similar to humic lignite. It may be possible to distinguish sapropelic lignites by their homogeneous, non-stratified appearance. If differentiation is difficult, sapropelic lignites can be accurately differentiated by chemical analysis. British Geological Survey Research Report RR/99/03, section 6.2, table 17 and fig. 10."@en . "stable"@en . . . . "Sapropelic-lignite"@en . "Sapropelic-lignite"@en . . "SLIG"@en .