1. The motto "E PLURIBUS UNUM" on coins with the meaning of "one out of many" is also the phrase on the Seal of the United States. It was adopted in 1782 at the time of the Seal's creation.
2. The official motto "In God We Trust" was adopted in 1956 as an alternative or replacement of the previous motto "E PLURIBUS UNUM".
3. Washington Quarters produced before 1965 were made of 90% Silver, which were worth more than $3 now. The quarters minted after 1965 are nickel and copper, worth just 25 cents. Bummer.
4. You can easily find the difference between quarters made before 1965 and after just by looking at the side. If you find one with sliver colored line instead of copper colored line, you will definitely want to keep it.
5. United States Mint currently operates six facilities. One facility is headquarter, one is for storage, and the other four produce coins. Only the Mint facilities in Philadelphia and Denver produce circulated coins. Mintage counts on the two places.
6. Quarters struck at Denver Mint bear a "D" mark on the obverse. Quarters struck at Philadelphia Mint bear a "P" on the obverse. FYI, touring to United States Mint in Denver or Philadelphia is FREE. It's a good place to learn how to "make money".
7. Unfortunately, you can't find any 1975 or 1976 dated quarters because of the United States Bicentennial. To honor the Bicentennial year for America, all the quarters minted from 1975 to 1976 issued the double date 1776-1976 on the obverse instead of 1975 or 1976.
8. United States Mint are designing and producing commemorative quarters for commerce and collectors since 1999. The Eagle featured quarters were then replaced by other images.
9. 50 State Quarters Program was launch in 1999 and lasted 10 years to honor states. 5 states were released each year following the order that they were ratified the constitution or were admitted into the Union. Delaware was the first state.
10. Each commemorative state quarter was produced for about 10 weeks and will never produce again. So hurry up, if you want to collect the out of mint state quarters.
11. Following the 50 State Quarters Program, United States Mint launched the 2009 District of Columbia and the Five U.S. Territories -- the commonwealth of Puerto Rico, Guam, American Samoa, the United States Virgin Islands, and the Commonwealth of the Northern Mariana Islands.
12. In 2010, United States Mint launched its new program—America the Beautiful Quarters Program to honor 56 national parks and other national sites in each state, District of Columbia and five U.S. territories. It will end in 2021.
13. The national park quarters were issued in the order on which the honored site was first established as a national site. Hot Spring National Park in Arkansas was released first.