Considered to be a highly variable pigment between raw umber (almost greenish brown) and burnt umber (a ruddier brown), Mummy Brown was a transparent brown good for mixing.
Made from ancient Egyptian human and feline mummies grave-robbed as antiquities in Europe, there was a craze to use the bodies for everything from fertilizer to beauty creams to fine art paint pigment.
The pigment itself wasn’t easily imitated. It wasn’t just made regular long-dried out corpses. The mummification process involved asphaltum or bitumen, often in place of the removed organs. Whole mummies were then ground for commercial use.
Via Scientific American.