hemosiderin(n = noun.substance) haemosiderin - a granular brown substance composed of ferric oxide; left from the breakdown of hemoglobin; can be a sign of disturbed iron metabolism; Array
a granular yellowish-brown substance composed of protein and ferric oxide, resulting from the breakdown of hemoglobin; it has a higher iron content than ferritin, and its presence in body tissues or phagocytes can be a symptom of disturbed iron metabolism. [WordNet 1.5]