Crystals, such as quartz, can be tapped for electricity using a piezoelectric (mechanical energy discharge) method. By securing the crystal and subjecting it to direct force with a permanent magnet, a detectable amount of electricity is released. This technology is used in cigarette lighters and gas grill ignition buttons; the unit requires no battery cell to operate. Continuously rapping on the crystal will produce usable electrical current. Making a small crystal electrical generator will take the average backyard inventor about a half-hour.
Cut the insulated wire into two parts using the blade section of the wire stripper.
Strip all four ends of the two wires, exposing about a half-inch of copper filament on each end. Twist the ends of the wires into tight coils if using a multiple-filament wire.
Solder each wire to the back of a separate electrode. The electrode should have an adhesive backing that will allow it to attach to objects. If no electrodes are being used, simply drop a large glob of solder onto one end of each wire, about half the size of a dime.
Attach one electrode to the quartz crystal by pressing the adhesive backing onto a flat section. Without electrodes, press the glob of solder against the crystal and secure with a couple drops of glue. Without glue or electrodes, strip the wire down to an exposed length that is long enough to wrap around the crystal tightly.
Attach the other electrode to the permanent magnet, using the same methods used to attach to the crystal.
Attach the two remaining wire ends to the voltmeter's electrodes (polarity is not important). Set the voltmeter for a low power setting (~1v).
Strike the crystal with the magnet, but not hard enough to cause damage. The voltmeter will show a spike when the crystal is hit with the magnet. By striking the two together repetitively, a current can be generated and stored.
TL;DR (Too Long; Didn't Read)
Use larger crystals and magnets for a larger discharge.
Use protective eye wear when striking the crystal.