Note:  Do not rely on this information. It is very old.

Haematin

Haematin, a coloured material formed by the decomposition by acids or alkalies of the haemoglobin (q.v.) of the blood. It is usually obtained as a scaly mass of a blue-black colour, which when powdered appeals dark-brown. It is sometimes found in the faeces, and in certain poisoning cases in the urine. It is usually identified by the spectroscopic examination of its solution.