圧し石[oshiishi] stone weight
一石[isseki] one game (of go)
一石二鳥[issekinichou] killing two birds with one stone
英国石油[eikokusekiyu] British Petroleum
下石[shitaishi] nether millstone

化粧石鹸[keshousekken] toilet soap
化石[kaseki] fossil
化石学[kasekigaku] paleontology
化石層[kasekisou] fossil bed
化石燃料[kasekinenryou] fossil fuel

硅素[keiso] silicon (Si)
硅砂[keisha] silica sand
硅石[keiseki] silica

硅肺[keihai] silicosis
硅酸塩[keisanen] silicate