well larger quartz crystals are used in industry to produce mega volts, I should imagine giga volts are not out of the question. The question is how high a frequency can the crystals be shorted and through what kind of load, amongst other things. I just don't have the equipment to iinvestigate further, or the resorces to research further into why it doesn't work. I assume it doesn't work because the idea is so blindingly obvious.

1kohm was think vor piezo (used in lighters  2000Volts)
older grmmophon pickup cartiges (200mv)
piezo microphones  50mV

If you use static Voltages from crystalls
(unknow to me) , but if Voltage over 100.000 Volt
must be "loaded" , use 100 Meg ohms and more.

Cheap avaiable resistors up to 30 Megohm , you find in ols TV-Sets.

Also , high resistor value > 1 - 100+ Megohm you can make self
with pencil paint (use:graphit-pencil) on an paper  (connectes wit alligator-clips)

  Just to help you a little, maybe the tension you mesure look like thermocouple effect. Simple explaination is 2 different king of alloy if they touch each other will generate a specific small tension like this one with temperature. We use it alot to make temperature sensor.

The trouble is they make VERY SMALL CURRENT, then no power...

Alp
Sergio

Well, it certainly seems like a good idea. From: http://en.wikipedia.org/wiki/Piezoelectric

QuoteA similar idea is being researched by DARPA in the USA in a project called Energy Harvesting, which includes an attempt to power battlefield equipment by piezoelectric generators embedded in soldiers' boots.

Wouldn't quartz between two large magnets be under constant stress?

if it give only (high) voltages and no (or small) currents.
it give no (small) power.  Volt x Amp = Watts

If you will see the (peak) voltages that comes from piezo , induction enz.

charge an small condensor via  an (fast) rectifier diode.

GP