What is the cost of a piezoelectric crystal?

The vast majority of devices that use piezoelectric crystals (piezoelectric buzzers, fish finders, atomic force microscopes, etc.) use crystals of lead zirconate titanate (PZT).

The crystal oscillator in a computer or digital clock uses the piezoelectric effect, but it is usually made of pure quartz (silicon dioxide).

Many different crystals and other materials exhibit the piezoelectric effect, including quartz crystals, cane sugar, and bone.