20th-century silver coinage was struck in 90% silver / 10% copper, so your coin has (0.90 x 6.25) gm, or 5.625 gm of pure silver. That figure holds true for all Barber, Standing Liberty, and pre-1965 Washington quarters.
At current silver prices you coin is worth about $3.
Updated for Apr 11, 2011
Currently a 1960 coin is worth around $8.77 in silver/copper
The value is about $3.00 just for the silver
The coin is not "all silver" its 90% silver and 10% copper. The value is about 3 bucks just for the silver content.
It is a common date and worth about $5.25 in silver content.
about $6.50-$7.50
The 1964 Washington Quarter has .18084oz of pure silver.
There is 2.25 grams of silver in a 1960 dime.
It is 90% silver and 10% copper.
$3.00
$50
If you mean a 1966 American quarter, then none.
Currently none.
$10