The Presidium Gem Tester is perfect for testing your gems for thermal conductivity.
The Presidium Gem Tester separates the most popular gemstones by testing their thermal conductivity. Also distinguishes diamonds from simulants (excluding moissanite). Comes with 2 test disks for calibration. Unit operates on a supplied AC adapter or 2 AA batteries (not included). Covered under a 1 year manufacturer's warranty,