Presidium Gem Tester Test Results: Identifying Diamond & Corundum

Question
Hellow Peter Lumetta,

Lately bought a Presidium Gem tester and tested some gemstones which were highly suspected of being rough diamond. At room temperature where the temperature has ranged from 25-29 degrees centigrade, all these stones gave a corundum (ruby,saphire) reading. In a cool room where the temperature was below 19 degrees centigrade, they are gave a diamond positive reading.Their other physical properties such as hardness, density, uv fluoresence, inclusions, trigons, crystal shape seem to be consistant with diamond rough. Which of this two results can I accept or what would be your opinion?

Regards,

David Timi

Answer
Hi Timi,

When testing gem materials I find if it looks like a duck, quacks like a duck and walks like a duck then it's a duck. Many times one test may say that a gem is another gem but all the tests say otherwise. Then go with the majority of tests. All the physical properties you have listed are positive identification for diamond. Anytime a piece of electronic testing equipment is used it should only be to confirm the results of the phsical properties. No matter what it says. It is diamond.

Peter