珪藻[keisou] diatom
珪藻土[keisoudo] diatomaceous soil
二酸化珪素[nisankakeiso] silicon dioxide (SiO2)
珪素[keiso] silicon (Si)
珪酸[keisan] silicic acid

珪砂[keisha] silica sand
珪石[keiseki] silica
珪性肺塵症[keiseihaijinshou] pneumonoultramicroscopicsilicovolcanoconiosis
珪素鋼[keisokou] silicon steel
珪素樹脂[keisojushi] silicone resin

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