成群的食鱼海鸟在天空中飞翔,它们群居在热带—亚热带的一些海岛上。海鸟的粪便在岛屿上长期堆积形成鸟粪层。海鸟的粪便中含有丰富的磷酸盐以及硝酸盐、铵盐和有机质等。鸟粪层经分解,有机质发生氧化,易溶的盐类被淋洗冲走,磷酸盐残留原地成为含可溶磷较高的粪土和粪石,经历数万年后便形成鸟粪矿床。鸟粪磷矿不象金属矿物和一般非金属矿物那样具有金属光泽或鲜艳夺目的色彩及晶形。鸟粪磷矿,有的呈块状、粒状、粉状,有的呈糠皮状,有的磷质下渗与珊瑚砂胶结或进行充填而呈多孔状或海绵状,颜 Swarm of fish-eating seabirds fly in the sky and live in some tropical-subtropical islands. Seabirds’ excrement accumulates on the island for a long time to form guano layers. Seabirds excrement is rich in phosphate and nitrate, ammonium salts and organic matter. After the decomposition of guano layer, the organic matter is oxidized, the soluble salts are rinsed away, and the phosphate residue becomes in situ native soil and fecal stone containing high soluble phosphorus. After several thousand years, guano deposits are formed. Guano phosphate rock does not have metallic luster or vivid eye-catching colors and crystalline forms, unlike metallic and non-metallic minerals. Gufen phosphate rock, and some were massive, granular, powdery, and some were bran-like, and some phosphorus infiltration and coral sand cementation or filling and was porous or sponge-like, Yan