1966 Quarter Weighs Like A Silver But Looks Clad?

I have a 1966 quarter that looks fairly normal except that I accidentally weighed it thinking it was 1965 and it turns out it weighs 5.74g. Now my scale only goes .01 so it could be off by a little either direction but still thats pretty darn close to 5.75.

The Strike It Rich with Pocket Change book doesn't list 1966 as a possible silver quarter year. But the wierder part is if I look along the side of the quarter I swear I can see a very feint copper line.

Only thing I can come up with is that its more silver then it should be and there is some copper but not enough to balance it out the way it should.

Ideas?

Sadly I could not get a picture of the side to show the slight copper line, atleast not with my camera. If you guys think you need to see that or really wanna see that I'll see if I can get my dad to do a shot of it. He is a non-paid professional photographer and does closeups of like fast moving humming birds n stuff lol.

Oh and I got this while roll searching so thats why I posted it here. If this goes somewhere else I apologize and I'll know for next time.

Thanks!

*** Moved by Staff to a more appropriate forum. ***