Arete synthetic-diamond tester by Gemtrue, 'Duo' model, includes a Diamond Experior tester Options_Mains Optional 5x 43mm Two pairs of

5x 43mm Two pairs of lenses + small  auxiliary lens 1x + 1

everything nicely presented in a large cardboard box

That's very easy with loose stones

RESOLUTION / CAPACITY: 20g / 0

Arete synthetic-diamond tester by Gemtrue, 'Duo' model, includes a Diamond Experior tester Options_Mains Optional 5x 43mm Two pairs ofSummary Arete synthetic diamond tester plus a free Diamond Experior thermal diamond tester. Between them, they test for natural diamond, synthetic (= lab grown) diamond, Moissanite, and "any other stone". The GemTrue Arete is an essential tool for the experienced jeweller and professional diamond dealer, it is for testing known diamonds, to see if they are natural or synthetic. That means you must first test the stone on a good quality diamond tester