I believe you can tell the difference in the stones. The one I was sent, looks nothing like the one I purchased. It was purchased through an online auction. I contacted the seller at gemrockauctions.com. The conversation with the seller is as follows:
26th Sep 2020nootkabear
My name is Janet McDonald. I won the bid on the following:
22.48 Cts Untreated Topaz Excellent Luster & Color Gemstone TP19
Won 3rd Sep via Bid
khanjee Auction ID 1275573
My item has arrived. I have some questions.
When I first looked to the stone, it looked like the center is clear – has no color at all.
So, I put it under my inspection camera, and when looking at it from the backside, it appears all clear, except the outside edges are blue.
When I turn it over and look at it from the top, one wide up to the edges is clear. The other side shows blue.
I took pictures so that I can send to you, if I need to.
Please advise, as I paid for a blue topaz.
29th Sep 2020khanjee
We’re very sorry for late reply. It’s because of fancy cut and sorry if you don’t like the stone. Please you can send it back, when we receive the parcel, will refund your full payment. Thanks
30th Sep 2020nootkabear
So you expect me to pay for shipping back to you, when your advertisement for the stone said nothing about it being part blue, and that the stone was irradiated to make it blue? I don’t think so.