No U.S. coins have ever been struck in pure silver. It's too soft for use in coins.
But yes, there are premium edition proof State Quarters that have been struck in a silver alloy of 90% silver, 10% copper. These coins have an S mint mark and are heavier than a normal quarter. They should be in their original packaging to be worth full value.
If you have a State Quarter that appears to be a solid metal but doesn't have an S mint mark and is the same weight as a normal quarter, you probably have a plated coin. There are hundreds of firms that take normal copper-nickel quarters, plate them, and sell them as "collectibles", usually at high markups. Sometimes a set gets broken up and the coins are spent. However these coins don't have any numismatic value so they're really only worth face value, 25¢.
We found the 2007 colored state quarter sets (with white background) on the internet and were able to purchase 2 sets. We have not been able to locate the 2008 set. Do a goolge search, maybe check Ebay for 2007. You can purchase them from 50 State Quarters web site but they are upgrading their site at the moment. They sell the colorized quarters with the white background.
In 2007 state quarters were issued for Montana, Washington, Idaho, Wyoming, and Utah.
In one short, firm word - NO. Nearly all of the "special" sets of state quarters, Presidential dollars, etc. that you see advertised in magazines are overpriced and overhyped. Steer clear.
It is possible that your quarter may have been coated or plated with a silver-colored substance, or it could be a counterfeit coin. The weight difference could also be due to the added substance. The US Mint does not produce silver-colored state quarters, so it is unlikely that it is an official coin variation.
US state quarters are made of a combination of copper-nickel (75% copper, 25% nickel) bonded to a copper core. This composition helps to create a durable coin that is resistant to wear and maintains its appearance for circulation.
No state quarters are made of silver.
can you buy state quarters
No they are NOT OFFICIAL and yes this is done by private companies and no it does not add to the value of the coins.
The last state quarters were released in 2008.
Common state quarters contain 0 silver, however there were special silver proof sets made for collectors, also some of the home shopping channels sold quarters plated in gold,silver & platinum.
You have a complete collection of 50 state quarters, CONGRATULATIONS!
The current plan is for 6 territorial quarters to be produced in 2009. In 2010, the plan is (or at least was) for 5 coins per year to commemorate one national park in each state (and territory?), effectively extending the "State Quarter" program to 2019 or 2020.