江西星子县玉泉山青石矿矿体为中元古界双桥山群上亚群浅变质含粉砂绢云母板岩。
The bluestone body in Yuquanshan of Xingzi , Jiangxi consists of a slightly metamorphosed silt-bearing sericite slate of the Middle Proterozoic Shuangqiaoshan Upper Subgroup .