Before you buy ANY David Yurman Jewelry on eBay, please do some research on
the items you're looking to buy. Companies in China are mass producing supposed
David Yurman jewelry, along with pouches, and even "certificates of authencity
The most commonly sold fake Yurman items on eBay that are found from this one particular Chinese company are the 11mm albion split shank rings with diamonds (in such "gemstones" as blue topaz, mother of pearl, onyx, rose quartz and amethyst) that retail for $950+, and the 7mm and 10mm bracelets with single stone ends.
This Chinese site is selling the pieces to eBay resellers for $110 each or less. Since the rings retail for more than $950, you will be able to notice a difference in quality right away. Please be warned that these pieces do have the DY stampings in them, further misleading a buyer into thinking it's authentic!
If you are looking to buy something, do a search on eBay, and see how many of the same item from the same seller pop up, day after day as a new auction. Ask for an ACTUAL photo of the item and not just the stock photo used. Yurman's diamonds in his pieces will ALWAYS be brilliant. If they look cloudy in a photo, use caution. Contact the seller, and ask about the piece. Compare the photos you're given to those on Yurman's website. Look at the details, like the stone size, and detailing on the metals.
Be wary of sellers that list the same item every day for a one day auction, over and over. Or those that have the same ring in every imaginable size and color. How many sellers are willing to put such limited auctions in place for a high dollar item if it's the real thing?? Most honest sellers will want to maximize the visability of their item and have longer auction periods, unless it's very close to an important holiday rush (Dec 15 & after, for example).
How can you be sure what you're buying is real? You can't from a photo. You can't based on the markings or hallmarks in the description of the piece. You may only be able to tell once you have gotten it in your hands.
A good seller will always offer a money back guarantee. I always tell my buyers to take an item to a Yurman retailer. If the retailer says the piece is not real, that should be more than good enough for an honest seller to take it back, and refund ALL costs associated with the transaction. Make sure if you are paying by PayPal, there is a guarantee from PayPal on the listing for at least the amount you're willing to spend.