一枚岩[ichimaiiwa] monolith
火山岩[kazangan] volcanic rock
火成岩[kaseigan] igneous rock
かこう岩[kakougan] granite
岩塩[ganen] halite

岩屋[iwaya] cavern
岩角[iwakado] edge or corner of a stone
岩間[iwama] among rocks
岩山[iwayama] rocky mountain

鴉片窟[ahenkutsu] opium den
仙窟[senkutsu] enchanted cave
巣窟[soukutsu] den
洞窟[doukutsu] cave
貧民窟[hinminkutsu] slums

魔窟[makutsu] den of thieves
偏窟[henkutsu] eccentricity
理窟[rikutsu] theory
巌窟[gankutsu] cave