What does "hemin" mean?

Hemin: A substance, in the form of reddish brown, microscopic, prismatic crystals, formed from dried blood by the action of strong acetic acid and common salt; -- called also Teichmann's crystals. Chemically, it is a hydrochloride of hematin. Note: The obtaining of these small crystals, from old blood clots or suspected blood stains, constitutes one of the best evidences of the presence of blood.