(一)发现的经过:我系在一九五一年夏天接到地委会叫我们调查胶东地质的任务后,就组织四年级同学及若干先生去胶东一带调查,十月三日在桃村灵山夼附近发现结晶极完美的正长石双晶及单晶,产在斑状花岗闪长岩中,我们认为像这样完美的正长石双晶,尚属罕见。我们为了矿物课堂作为正长石双晶示范之用,又为了贯彻 (I) After the discovery: After receiving the commission’s request from the local committee in the summer of 1951 asking for the investigation of the Jiaodong geology, we organized the investigation of the fourth-grade classmates and some gentlemen to the Jiaodong area. On October 3, Near the mountain of Lingshan, we find that the perfect crystalline anorthite bi-crystal and single crystal are produced in the porphyritic granodiorite. We think it is rare that such a perfect anorthite crystallizes like this. We are using mineral fossils as an example of feldspar twins and we have to implement them