Hemosiderin is a hemoglobin-derived pigment, a golden-yellow or brownish-yellow granule, which is called iron-containing hemosiderin because of its iron content and golden-yellow color. When erythrocytes are phagocytosed by macrophages, hemoglobin is broken down into iron-free orange hemoglobin and iron-containing iron-containing hemosiderin under the action of lysosomal enzymes.