Glistening wax like substance, not a true
oil, contained in the cells of the huge,
almost rectangular `case' in the head of the
sperm whale, amounting to about 2.5 tonnes.
It rapidly changes in density according to
temperature. It was formerly used in
lubricants and cosmetics, but in 1980 a blend
of fatty acids and esters from tallow and
coconut oil was developed as a substitute.