Heat would pass a diamond differently than it would through cubic zirconia or glass or as a matter of fact any other gemstone. A Diamond Tester can't be wrong, will detect the rate at which the heat moves through the stone. The new electrical devices are also available in the market today.

Can fake diamonds pass diamond tester?

There are different ways to diamond test. It's important to know which tests synthetic diamonds will pass and which they will fail. Carbon lab diamonds can pass tests in terms of their physical and chemical properties, but when these synthetics pass in front of experts, their difference are quite apparent.

Are diamond testers accurate?

Diamond testers are one of the most accurate tools to check a diamond for authenticity. ... This problem is solved by using a device that uses electrical conductivity to test stones – diamonds and moissanites conduct electricity differently.