gem gravels

例句：

1. 1. The gemstone in the necklace is worth thousands of dollars.
   项链上的宝石价值数千美元。
2. 2. The cobblestone road was uneven and made walking difficult.
   鹅卵石铺成的路面不平，走路很困难。
3. 3. The pebble beach was a popular spot for tourists to collect seashells.
   小石子海滩是游客收集贝壳的热门地点。