The external skin of the Mercury spacecraft, except for the heatshield, was made of two types of metal shingles. The conical part of the spacecraft was covered with shingles like this one of a very specialized nickel steel alloy called Rene 41. These could withstand the high heat of reentry due to their high melting point and ability to radiate away much of their heat. The conical nose of the spacecraft had even more exotic and heat resistant beryllium shingles.
This Rene 41 shingle was mounted on Gordon Cooper's Faith 7 capsule during his 22-orbit, 34-hour, Mercury-Atlas 9 mission on May 15-16, 1963. In 1971 NASA transferred this shingle to the Smithsonian.
This object is not on display at the National Air and Space Museum. It is either on loan or in storage.