Large Blue Gemstone - Topaz? Vintage ring.

[avidcollector]

Hello,
I bought this lovely, vintage ring. Hallmarks would indicate it was made pre-1975. The stone usually looks lighter in real life.
It shows strong pleochroism, clearly showing dark purple at certain angles, and on the widest face under certain lights. Generally it looks quite light blue (lighter than the camera picks up on).
Under lw uv it shows as orange or orange/pink ...
It is a big stone, measuring about 1.5cm in length.
I have read the topaz has low pleochroism, so would be interested on people's opinions. I have had darker blue topaz that has only shown various shades of blue play.
Whatever it is it is definitely spectacular!

 

[stracci2000]

It's pretty! Being that it is set into 9 ct. gold, I'm going to say that the stone is synthetic.

 

[shelovesinclusions]

Synthetic blue spinel will glow orange red under a lw uv.

 

[avidcollector]

Thanks - I would be fine with it being synthetic / lab grown spinel or another type of lab grown gem. I'm just curious as to what it is.

The purple colour shift is really lovely, and very obvious (although I haven't managed to photograph it well). I find it very pretty, even as a synthetic. The shift in colour covers a large area of the stone at times (about 50-70 percent), but I don't think it's actually a colour change stone.

It was obviously a loved ring, since a 9ct ring size reducer has been added (unfortunately the sliding effect of this has rubbed off the date stamp).

I don't think heat treated topaz is particularly valuable, so could be set in 9ct gold., but I also don't believe this is topaz of any type.

 

[avidcollector]

Updated snapshots of colour, but please note the brown areas look more purple in real life, and that's what I thought I was photographing.
Although sometimes there is brown at certain angles

It is transparent enough you can see print through it, which makes photographing it hard as the backgrounds show through.
The UV picture should show more of an apricot or peach orange

I actually thought it might be glass when I first got it, but the age and lack of wear on the facets changed my mind.

**
EDIT: I have just realised the colour is probably from the setting showing through the facets. Duh. Still interested in the uv reaction though.

**

 

[Daisys and Diamonds]

would love to see a hand shot
its very pretty

 

[avidcollector]

Thank you Daisys and Diamonds. My hands are awful and don't do the ring justice. Gardening etc., takes a toll, so I'm too embarrassed to take pictures of them.
I think Miss Sarah hit the nail on the head with synthetic spinel. I have seen a number of listings with similar stones that are all spinel.
Thank you everybody ^_^ It's really nice to have that mystery cleared up.