Unfortunately, there is a raft of Chinese counterfeiting gold coins and silver bars. They can match the desired density of the metal by using precise amounts of tungsten. Clearly the counterfeiting is state sponsored as the quality is very high.
(Do a quick search on counterfeit bars and you will see how many are out there..)
To sell the bar you will need some document that attests to its authenticity. That is tough.
Find the buyer who buys the “precious metals” from pawn shops and they will test and buy the metal from you. However, be sure to ask what percentage of “spot price” they are paying. You will otherwise sell for a greatly reduced percentage.
@jaytkay I am unsure that a small, 10 oz. bar, would require any sort of documentation. However, the person wishing to sell it would require some identity papers.
Should I simply eBay it? It looks like they are going for $400+ on eBay. I would be happy to get $375 or more. When I received the bar as a gift, the price of silver was about $5 US.
Should I shine the bar? It’s very slightly tarnished.
I would go to a reputable coin dealer in your area. The value of silver is set by the market. I had a sterling silver bowl that I took to a coin dealer and he weighed it, checked the current price for silver and gave me basically what it was worth minus a small handling fee. Coin dealers buy and sell gold and silver regularly and are generally knowledgeable and honest. And the value of precious metals is all about what it weighs and it’s purity, not how shiny is is. The dealer will probably be able to tell to his or her satisfaction whether or not the bar is real. Anyway, I would start there.
I would take it to two or three reputable coin and jewelry dealers in your locale and get quotes. Let them know upfront you are going to get more quotes (it’s likely to make them more honest) before you sell it. By the end of the day, you’ll know if you want to sell it locally or want to try your hand at eBay.