Test for Real Germanium Diode or Fake Schottky imports from China

This is a limited, but good first test to see if the "Germanium" diodes you bought online are real Germanium, and not fake silicon Schottky diodes.
Test: Germanium diodes have reverse leakage currents.
Schottky diodes have little to no leakage at small voltages.
Important for guitar pedals, radio, etc.

NOTE: A 9v battery works the same, and shows more reverse leakage, in case your meter is not super sensitive in the micro-amp (μA) range. (Thx KJ6EAD). For the record, this meter was $29 at Harbor Freight. Not super accurate or robust, but it was sensitive enough for this demonstration.