I think we've been over this before but...gem testers

I need to get a gem tester now, but before I get a 20 euro one on amazon, are they good enough for at home/ebay sales? I need one that is reliable enough to test other stones, like the rubies on my boxes. The jeweler said she couldn't test them with the same one she tested the diamonds, but I know many people here use it for that purpose. Do I need a 500 euro one to put items up for sale accurately, or will showing a photo of the test being done be enough to satisfy a buyer and keep me from being an inaccurate seller?

Thanks!​

 

I have a cheap diamond tester, it tests the Mohs hardness, also of rubies, agates, any other stone. Mine works fine. But if you want another type of tester, it will cost you more.

 

Great, thanks!