Will lab emerald test as an emerald or glass?

[RMOO]

With a Presidium tester?

 

[Autumn in New England]

Those testers are just so unreliable for colored stones, in my experience. So I'm not much help in that regard. But any qualified G.G. or lab (or even an experienced gem geek with the right tools) should be able to easily differentiate between lab emerald and glass. Good luck!

 

[Bron357]

Presidium tester work on the heat signal and can be useful in some circumstances. Yes, they can ID glass from everything else but they can’t tell you if a material is lab grown and / or treated. Because treatment ie flux filling, high heat, diffusion matters a lot with some gemstones it’s best to submit to a lab.