Generally, the instrument is a check, cash or a credit card.
If, however, you want to verify that the stone that you are buying is a diamond, you need a diamond tester.
Rheostat is the name of an instrument used to vary electrical resistance.
syringe
Timepieces.
polytechnic drawing instrument
Telescope.
Bongos.
A set square !
It is Thermoscope
Electronic microscope
a compass i think
Amy diamond was a name once concieved but never used by a student journalist,derived from The Diamond newspaper in Victoria
The instrument used to measure the volumes of liquids are many as follows ..they are : beaker ,burette,pipette,etc.