piezoelectric crystal - one showing piezoelectric properties which may be shaped and used as a resonant circuit element or transducer (eg a microphone, pick-up, loudspeaker, depth-finder etc), piezoelectric effect - electric polarization arising in some anisotropic (ie not processing a centre of symmetry) crystals (quartz, Rochelle salt, barium titanate) when subject to mechanical strain, kvartsiteisend, peamiselt mäekristall, millest saab valmistada piesoelektrilisi detaile, kvarts, millest saab valmistada piesoelektrilisi detaile (neid kasut. peam. raadiotehnikas generaatorite sageduse stabiliseerimiseks). Looduses leidub piesokvartsi pegmatiitides. Looduslikku piesokvartsi asendab ulatuslikult tehispiesokvarts.