noun
broken stones; rubble
Refers to stones that have been broken or crushed, often used in construction, roadwork, or as a raw material.
道路の下に割り石を敷き詰めた。
They laid broken stones under the road.
割り石を砕いて砂利にする。
They crush broken stones into gravel.
Compound of 割り (wari, 'breaking') + 石 (ishi, 'stone'). The reading わりいし is a straightforward combination.