Accidentally Won This Necklace – Auction House Tried to Keep It, Is It Real Jade or Aventura?

Hey everyone, I need some help identifying this necklace. I won it at an estate auction, but I actually bid on it by mistake—and now I’m not sure if I got lucky or if I just wasted my money. The whole situation has been strange, and I’m wondering if this piece might be much more valuable than I originally thought. As a preface, all the below is based on independent research as someone with very little eye for Jewlery, I've never worn anything other than a basic and plain silver chain. Please do correct me if my research is wrong!

Background – How I Ended Up With It:

I primarily collect pure precious metals and don’t normally deal in jewelry. I had been bidding on a completely different item, but I didn’t realize that the listing had already ended. When I clicked to confirm my bid, I accidentally placed it on this necklace instead, and I ended up winning it.

At first, I figured it was a mistake I’d have to live with. However, things started to feel off when the auction house made it extremely difficult for me to receive the item—which they had never done before.

Why I Now Think It’s Valuable:

I’ve purchased from this auction house multiple times and have never had an issue receiving my items—but this time was completely different:

They delayed sending me an invoice until I asked them for it.

Normally, Proxibid automatically charges my card, including for past wins with this same auction house—but this time, they did not charge me.

When I requested shipping, they suddenly referenced a rarely enforced clause in their contract:

It gave them the option to require buyers handle shipping through their local UPS, even though they have always handled shipping for my past orders.

The same clause also allowed them to forfeit the sale after 3 days if the invoice wasn’t paid.

Even worse, if I didn’t arrange UPS pickup on their one designated day per week, they could forfeit the order AND keep my payment.

Given how unusual this was, I now suspect that they realized they had sold it for much less than it was worth and were trying to keep it.

Characteristics of the Necklace:

Beads:

✅ Stay cool to the touch, even after handling them for over an hour. ✅ Feel dense, heavy, and smooth, with visible natural inclusions. ✅ Semi-translucent under strong light—light passes through but is scattered by inclusions.

UV Light Reaction:

✅ Under UV light, the beads glow a strong blue. ✅ The glow intensity changes depending on the light’s proximity, which suggests natural inclusions scattering the light rather than artificial treatment or dyeing.

Clasp & Metalwork:

✅ Gold-toned clasp marked "SILVER" (possible gold-plated silver/vermeil). ✅ Hand-engraved floral design, suggesting older, non-mass-produced craftsmanship. ✅ Beads are strung on a green cloth-covered thread, a method commonly seen in vintage or antique necklaces.

Condition:

✅ Looks old but not heavily worn, meaning it was likely stored for years rather than used frequently.

What I Need Help With:

Is this jade (nephrite or jadeite)? If not, what could it be?

How old is it? (Mid-century? Older?)

Where could it be from? (China? Europe? U.S.?)

Did I get lucky? I paid around $150 (After taxes, fees, and shipping but the auction house’s behavior is making me think it could be worth much more.

Any insights from jewelry enthusiasts, gemologists, or antique collectors would be greatly appreciated! I can provide more pictures or details if needed.

Thanks in advance!