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Loose stones at auction houses?

Hello everyone. I’m new to the IGS family and I wonder if anyone has any experience or advice regarding purchasing loose gemstones from an auction house? I’ve been researching jewelry auctions (Christie’s, Doyle, Sotheby’s, etc.) for design ideas and I’ve seen a few lots that have loose stones.

  1. Avoid Ebay.

  2. Gem Rock Auctions is a decent site to work with, but be mindful of where the different shops are shipping/selling from and be most careful with shops shipping from Asia.

  3. If you are able to visit an Auction house in person, bring a small tool kit with you that has a couple of loupes, penlights/torches of varying intensities (with one being a decent UV light), dicroscope, filters, and other items that can be fit into a small pouch.

  1. Most of ebay is trash, but you will find some decent sellers. If you have a return privilege and use Paypal and a credit card, you have lots of options if things go bad. If you message the seller with questions, you can get some insight into how they operate, how knowledgeable they are, etc.

  2. I don’t have any experience buying from GermRockAuctions, but I do look there to research prices.

  3. Yes, if you can visit an auction house, take your pocket instruments with you. The Hanneman filters are great, too, if you have them.

  4. The big auction houses might have things you can use…just see whether they are standing behind their ID or not. I don’t think you can rescind an auction unless the description is way off.

  5. You really do have to have a good idea of valuations, or you will get skinned. Research prices on line and/or have a good appraisal/value tool and know how to use it. The Gemworld Guide is good for grading color if you have the World of Color book, but their prices are usually considered way high…but as a relative value they are useful…just know what the multiplier is…30% or 50% or whatever. I know folks who use the Gem Guide prices without the color reference, but color is so critical with colored stones that I think this is misguided. Shades of color make a big, big difference, which is why white backgrounds in photos are so important. If you see a color cast, beware!

  6. Be aware that loose stones may be chipped and need to be recut.

Firstly, and if possible, get a written copy of their conditions of sale. Does the auction house give full details and warrant the identity of the stone as a specific mineral ? Does it have a return policy if the stone has been misidentified by them or is from a location different from the one stated? Please note that a term such as “garnet” is not sufficient eg is it hessonite or pyrope etc ? . Be aware that terms such as “natural” and " not heat treated" cannot be easily verified by simple means. In particular be wary of “natural zircon” both colorless and in all different colours and particularly from Indian sellers. These are usually synthetic cubic zirconia aka zirconium oxide masquerading as zirconium silicate but can be discriminated from sapphire and spinel etc by its higher SG. In short, buyer beware!

Avoid buying from China and India on eBay for the most part. If the deal looks too god to be true, it is! I’ve made some great buys on eBay in the past. It’s been a few years ago. Gemrockauctions has some good dealers as well. You have to pay attention to what you are buying because you may end up with a stone that is cracked, chipped of has a bad cut to begin with. I’ve found some nice stones there as well.
Welcome and all the best.
Otter.