noun · a dense, bluish-grey rock, typically a variety of limestone, used as a construction or paving material

古镇的小巷全是由青石铺就的，显得古朴典雅。

noun · the colloquial name for limestone, especially when referred to as a raw material for industrial use

这里的青石矿藏非常丰富，是烧制石灰的上等原料。