What was the latter coin, exactly? Was it something from a shipwreck? And what sort of evidence did they give that Arthur C. Clarke was involved at all? I'm a little wary of their guarantees given their gross misidentification of the coin you bought.
First off my brother bought it not me and we know it's real because the owner of the store has a picture with him and a picture of him holding the coins he sold to the store and in the store there is a paper certifing that he sold those coins to the store and it's signed by him.
also the store is very reputable because treasure hunters come in there to sell there stuff everyday and it was rated the best antique shop in St.Augustine
It was a dutch east india Comany duit discovered in sri lanka when he was making his documentery on his discovery of the Taj Mahal treasure he even brought his clump of rupies as seen on pawn stars to the store and the owner got a picture with it the store is called S.O.S Antiques in St.Augustine Fl if you are intrested they have lots of shipwreck and ancient coins
The Arthur C Clarke find is pretty well known, heck they had a group "staged" on pawn stars once. Nothing incredible though, fairly common coins. AncientRomeCoin, yes you coin is genuine. The store you are talking about though I believe is pretty high priced, and knows little to nothing on ancients. Your certificate is proof of that, most ancient collectors in a few months would tell you that coin was minted decades before Constantine. I would suggest getting a book or two, read it, go to coin shows where you can see real ancients in person, attend coin clubs where you can learns tons of stuff, maybe even read threads here and maybe subscribe to some Yahoo newsgroups on ancient coins. lots of resources now for young collectors. Most shops like the one you listed are for people who do not have much knowledge and want a curiousity for the sake of it, not serious collectors. Not trying to impune the shop, but honestly there just aren't enough ancient collectors around any one area to have serious ancient stores in most locales. Edit: Go to Doug Smith's website too! Great stuff.
I'll ask you. Do you like it as well as the coins I posted from my Baltimore show purchases that cost between $10 and $20? Quintillus is a slightly premium emperor so I would say it is worth a bit more than a coin in the same condition of, for example, Constantius II. At $20, the coin is neither a great bargain or a giant rip off. Many people get taken much worse on a first coin. Your goal needs to be to make the next purchase even better. Try for something you can identify without our help. We are happy to help but you need to learn to read the coins also.
Good point that I need to pick them with out help the only reason I am asking so many questions about this coin is that this is the first coin in my ancient collection and I am only 13
I agree with Doug, though I would like to point out that if the coin really have been a common Constantine type like the dealer thought it was, you would have paid too much. I wouldn't go back to him, at least not until you know what to look for.
I agree too, you are lucky you did not get what the certificate says it is. You got a somewhat scarcer emperor, in nice condition. I did much worst on my ancient coin, and I was 25 when I bought it!
...and I agree with Gao regarding doing your shopping elsewhere. I would bet a better coin that the dealer could not ID this one and probably not tell you most of the coins he sells. Also be well aware that we all pay too much for some coins and get bargains on others. It all evens out in the end. Keep this coin and in 50 years be very proud if it is your biggest miskake.