Well, actually, if a silver quarter costs $6 as you say, a ounce of fine silver costs about $34. I guess you could might as well buy some 2nd hand Maple Leafs or so for the same price. And then you have true .999 silver, which is better to sell than melting scrap silver.
We used to have coins with a silver part, but they are rare today. It was way back in the 60s and earlier and it was D-Mark then, so the government has long taken them out of circulation. If you find some now, they are worth more than just the silver, as collector coins.