Mineralogical Characteristic and Geological Significance of Garnet in "Hua'an Jade" from Fujian Province

"Hua'an jade" is an advantageous mineral resource in Fujian Province. Previous studies on "Hua'an jade" have been carried out systematically in terms of geology, petrology and mineralogy, but its formation mechanism has been controversial. In this study, the newly discovered garnet minerals in "Hua'an jade" were studied by means of systematic microscopic observation, SEM and EMPA technology. Through the field investigation and microscopic observation, garnet minerals in "Hua'an jade" can be divided into two stages. The early stage is micro-grained aggregate and the late stage is micro-vein or linear vein. Electron microprobe analysis showed that garnet minerals are mainly andradite, followed by grossular and almandite. The study of garnet minerals confirmed that the origin of "Hua'an jade" should be skarn type and multi-stage formation. The formation of red "Hua'an jade" (garnet-bearing minerals) is closely related to the distribution of regional granites, mainly distributed in the basement granite body as residual caps (such as Mianzhi county and Jiuqu county), but garnet minerals are rare or not found far away from the granite body.