The Diamond Tester Pen Myth: Why Your $20 Tester Can’t Tell a Natural Diamond from a Lab-Grown One, It’s a Useless Tool.
Cheap “diamond tester pens” promise peace of mind for $20. Touch the tip to a stone, hear a beep, and you know if it’s real… right? Here’s the problem: those pens only check how a stone conducts heat (and sometimes electricity). Natural diamonds and lab-grown diamonds are both crystal carbon with the same heat flow. […]










