Electron microprobe analysis (EMPA) and X-ray diffraction (XRD) were used to study the chemical and structural differences of a series of natural tourmaline crystals including six species respectively from Xinjiang (XJF, XJ and XJZ), Yunnan (YN), Guangxi (GX) and Brazil (BXL). The results indicated that the species XJ, YN and GX are schorl, XJZ is dravite, XJF is elbaite, and BXL is tsilaisit. The FeO contents of the three species XJ, YN and GX are in an order of XJXJ>XJZ>BXL>YN>GX. The result may be caused by polyhedron distortions of YO₆ octahedron. It can be concluded that the ability of formaldehyde purification will increase along with the increased mesh number.