It commemorates our Centennial as a nation. Probably doesn't have much of an inflate value over face.
This Canadian 1 cent piece, commemorating the 100th anniversary of the Canadian confederation, is worth no more than a few cents unless in Brilliant Uncirculated condition.
Please check your coin again and post a new, separate question. The first Canadian quarters were dated 1870.
You can sell it for either the price of all the quarters put together or how much the bidder wants for it. I have sold one on eBay for a lot and some people can get pretty crazy about them and bid really high. Also if you have it in a special thing that holds it that is in mint condition that shows which state and other stuff then that can bring up the value a lot.
No US quarter is dated 1782.
There were no quarter dollar coins issued by the U.S. mint in 1788.
No US quarters exist dated 1931.
A US quarter dated 1915 does contain 90% silver, so yes it is silver
The bicentennial quarter is extremely common, still worth 25 cents.
It's worth exactly 25 cents.
There are 5.625 grams of pure silver in every US quarter dated 1964 or prior.
A U.S. quarter dated 1965 or later weighs 1/5 of an ounce. Grab your calculator and go from there.
No U.S. coins dated 1966 have a mint mark. The '66 quarter is worth 25 cents.