curly schist

例句：

1. 1. The curly schist is a rare mineral that has been mined for centuries.
   结状石炭岩是一种稀有矿物，已经被开采了几个世纪。
2. 2. The curly schist is used in the production of cement and bricks.
   结状石炭岩被用于生产水泥和砖。
3. 3. The curly schist is a valuable resource for mining companies.
   结状石炭岩对矿业公司来说是宝贵的资源。