noun
Refers to small stones or gravel, often used in geological or construction contexts. Can also appear in literary descriptions of pebbles.
川原で色とりどりの礫を拾った。
I picked up colorful small stones at the riverbank.
この地層には丸い礫が多く含まれている。
This stratum contains many rounded gravel stones.
小石 is the common everyday word for 'small stone' or 'pebble'. 礫 is more formal, technical, or literary.
砂利 refers to gravel as a material (e.g., for roads or gardens), while 礫 can refer to individual small stones or gravel in a more general sense.
The kanji 礫 is a phono-semantic compound: the stone radical 石 combined with the phonetic component 樂 (simplified to 楽 in modern Japanese). The reading れき is the on'yomi. The word is primarily used in technical or literary contexts.