What gem is this - thoughts please.

[Bron357]

Hi everyone, this ring I've had for over 20 years, bought it at a secondhand shop, it's a lovely, hand made 14kt gold setting with a huge lime greenish colour stone. At the time I thought it was just glass or treated crystal of some type. It's a rather unusual colour and I bought because I loved it. People often ask "what is that???" And I've said (over the years) green Quartz, peridot, tourmaline ??? However, since purchasing a Presidum gem tester I have found that it tests in the Topaz range. So any thoughts as to what this weird lime green lump might be?

 

[Bron357]

Another possibility is green spinel (same range on the gem tester) and I found this image of an Art Deco ring with green spinel and ruby and mine stone is a dead ringer in my opinion.

 

[pokerface]

I have seen this sort of material before but the name of it is slipping my mind. 99% sure it is glass. The second ring posted most likely is synthetic spinel.

 

[Desertrose]

I've seen ones like this on Etsy, they are synthetic spinel made with uranium. Here's one:

https://www.etsy.com/listing/400935345/lime-green-spinel-ring-diamonds-10k-gold?ga_order=most_relevant&ga_search_type=all&ga_view_type=gallery&ga_search_query=green%20uranium%20glass%20jewelry&ref=sr_gallery_5

And here:

https://www.etsy.com/listing/198044744/uranium-glass-ring-spinel-vaseline?ga_order=most_relevant&ga_search_type=all&ga_view_type=gallery&ga_search_query=green%20uranium%20glass%20ring&ref=sr_gallery_6

They should glow under black light, and have low level radioactivity. You can find them under "uranium glass".

 

[DDOC]

Synthetic Spinel Bron.
I have a 30 ct emerald cut one in the safe somewhere. London Blue Topaz colour.
They cost about 10 cents a carat, plus cut fee.

 

[index_finger]

synthetic spinel?
Does it color change? Another possibility is synthetic alexandrite?