What is the value of a 1970 US quarter?
25 cents. 1970 quarters are still in circulation and are not rare.
The only ones that are worth any significant premium are quality uncirculated ones. As of 05/2010 prices range from about $1 for lower-quality uncirculated coins to perhaps $30-50 at the high end.
25 cents if in circulated condition, a bit more if the coin is proof or uncirculated. They contain no precious metals and are common finds in pocket change.
They are worth a minimum of $2 and if in perfect condition $8 and up. Depends on the buyer. (for this specific 1970 US quarter)