Results 1 to 3 of 3

Thread: Plastic ,Glass or Stone ?

  1. #1
    Join Date
    Apr 2015

    Default Plastic ,Glass or Stone ?


    My gem knowledge is incredibly basic. I'd love to have gone on a Gemology course but I joined in this wonderful trade far far too late to consider doing a gemstone course as well as learning the entire making proccess from the begining.

    I however, have got access to a digital refractometer, this helps massively but I got totally stumped the other day, as the batteries ran out and I had no replacements, a customer turned up looking to sell a ring and I had no way of knowing what the "Stone" was.

    One was a Black cabooshon oval stone and the other a flat Black signet ring set stone.

    My guess was they were Onyx, so based on this I made the guy an offer, explaining honestly my inexperiance and he was happy with the price I offered.

    He did tell me, he couldn't be sure if the stone was Plastic,Glass or Onyx....So without a refractometer, is there a way to tell these apart easily ?

    Thank you

  2. #2
    Join Date
    Dec 2009
    Central London


    Yes, but he might not have liked it. Plastic will burn, and glass will melt. The essence of a good deal is that both parties are happy.

    On a more serious note, there is a myriad of black stones as seen in the link below, but the metal of the ring would give a clue as to the order of value. In fact it might be the only valuable thing about it. So a hallmark would be the first thing to look for. Dennis.
    Last edited by Dennis; 24-11-2017 at 09:06 PM.

  3. #3
    Join Date
    Apr 2015


    Thank you....But without damaging the sellers property, is there any way to tell if the "Stone" was either Plastic,Stone or Glass ? The rings were 958 Silver hallmarked.


Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts