Dear Tudor,

First of all, you are absolutely right about the color – it is quite far from great. It is rather easy to understand why they have used 10ct gold for this ring. I mean, 10ct gold is normally used for inexpensive jewelry with rather low-quality gemstones.
I have bought and sold may pieces of tanzanite jewelry in my life, and my estimate is that this ring’s true market value is around $200. I would never pay more than that for it. So, yes, $552 is rather steep.
Unfortunately, I haven’t been dealing with 10ct gold jewelry for some time now. Therefore, I cannot suggest you any alternatives right away. However, it might be a good idea to browse through eBay, for example. I’m absolutely sure you will find much better deals there in no time. Use the keywords “gold”, “ring”, “tanzanite”.
As a matter of fact, $552 would be an adequate price for a 14ct ring with a better-quality tanzanite.
It would be great if you could come back afterwards and tell us how did it go.
I hope this helps.

Best regards, Editor

Dear LR,

I would say this is not so much about trust in the seller, this is rather about trust in the item. As you didn’t share the link, it is impossible to evaluate whether the seller is reliable. Thus, it might be a good idea to edit your question and share the link to this auction. In any case, the mere fact that the seller has been selling alike necklaces in the past does not mean anything. A seller can have several similar items available. That’s perfectly ok.
I believe, the main question here is whether these pearls are real. Unfortunately, it is quite difficult to tell for sure on the basis of this single image. You have to look for the growth marks. Natural pearls always have growth marks. Very high-quality pearls have very few growth marks but still, they have them, and a professional seller will take images showing them. Faux pearls, on the contrary, have no growth marks. So again, it might be a good idea to share the link to see more images.
The clasp in itself does not prove anything. I have seen both Akoya pearl necklaces and faux pearl necklaces coming with clasps like this. JKA stands for German company J. Köhle GmbH. To the best of my knowledge, they have been manufacturing both real pearl and faux pearl necklaces in the past. More importantly, it is not uncommon that pearl necklaces get re-strung. Thus, this is not necessarily its original clasp.
To sum it up, the first impression is that this is a legit Art Deco Akoya necklace. However, more close-up images are needed to tell for sure.
Last but not least, do not rely on the price estimates given by Catawiki’s experts. These estimates are highly inflated (especially for items with reserve prices). I have been following thousands of Catawiki auctions, and there is always the same pattern – the true market value is 20 – 30% of the estimate. This case is not an exception.

Best regards, Editor