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

一閃[issen] flash
閃かす[hiramekasu] to brandish
閃き[hirameki] flair
閃く[hirameku] to flash (lightning, etc.)
閃光[senkou] flash

閃光電球[senkoudenkyuu] flash bulb
花崗閃緑岩[kakousenryokugan] granodiorite
紫電一閃[shidenissen] flash of lightning
電光一閃[denkouissen] flash of lightning
閃緑岩[senryokugan] diorite (a type of rock similar to granite)