石塊 is read as せっかい (sekkai) and means stone.
せっかい
sekkai
せきかん
sarcophagus
いしがき
stone wall
せきひ
stone monument
せっき
stone implement (e.g. stone age arrowheads)
せっきじだい
Stone Age
いしはらは
Ishihara faction (of the Liberal Democratic Party)
いしいこうさくけんきゅうじょ
Ishii Tool & Engineering Corporation
groundmass
いしかわけんりつかんごだいがく
Ishikawa Prefectural Nursing University
せっきぶんか
stone age culture
せきゆかがくせいひん
petrochemicals
せきせいひん
stone artifact