natural crystal

例句：

1. 1. The naturalcrystals in the riverbed are awonder to behold.
   河床中的天然晶体令人惊叹。
2. 2. The mineral crystals inthe mine were worth thousands of dollars.
   矿中的矿物晶体价值数千美元。
3. 3. The crystals have been used for centuries as asymbol of purity and strength.
   这些晶体自古以来一直被用作纯洁和力量的象征。