Morning,
The only way is experience. If you had found a Roseville bowl at the sale for $10 bucks, how would you tell its authentic and not a Chinese knock off? Answer is study roseville, the marks, the patterns and best of all look at other both authentic and fake pieces to tell the differences.
Having said that, a ten buck investment is not much to make. If you liked the way the point looked as an art object then that was a cheap price to pay. If you were buying it thinking its worth a thousand, you might get lucky, but chances are you wont. Kinda like buying those 50 dollar Clovis points off eBay....lol.
Even experts can be fooled by a good fake arrowhead. The technology is getting so good now that most everything can be duplicated right down to artificial patina which is hard to distinguish from the real thing. Someone with no experience is lost, someone with years can be fooled. My suggestion to you would be spend little on a point. If you buy, do it from a reputable dealer or from someone you know personally that you can hurt if it turns out to be faked....lol
Other than that...Overstreets Guide gives good photos and descriptions of points...a book I recommend is called Relics and Reproductions, by James Bennet. It gives good descriptions and photos of ancient and reproductions points and ground stone artifacts as well as what to look for to differentiate them. There is really no pat answer to your question. Even the best can be fooled.
Hope this helps,
Atlantis
