Quarter
From Halopedia, the Halo wiki
A quarter is a 25 Cent piece used in the 20th-21st Century. By the time of United Nations Space Command, this currency was discontinued. These Quarters became valuable antique piece. One side has a picture of George Washington, and the other an eagle. Doctor Halsey used this quarter to test the would be spartans to check their visual capablities, as a reward, she gave the quarters to the them.
