Abstract: The radiated colony coral fossils with distinctive patterns and colours from Turpan,Xinjiang,is of highly gemmological value.The gemmological characteristics of the coral fossils are studied by using polarizing microscope,micro-hardness tester,EPMA,IR and X-ray powder diffraction.The results show that it is mainly composed of calcite with some dolomite and organic matter(containing methyl and hydroxyl).It is a calcium-based coral fossil.And the cause for the change of cell parameters in calcite is also analysed by calculating.In addition,the possibility of development prospect for the coral fossils from Turpan,Xinjiang,as gem resource is discussed.