grave wax
mortuary wax
corpse fat
lipocere
adipocere

They suggested that the heart had been saponified (turned to grave wax) under airless burial conditions, and then changed to goethite, an iron mineral, by replacement of the original material.

For soap making, the triglycerides are highly purified, but saponification includes other base hydrolysis of unpurified triglycerides, for example, the conversion of the fat of a corpse into adipocere, often called "grave wax."