This metallurgical trial, the third of three varieties, was produced by the International Nickel Company in 1965. They were one of several companies the U.S. Mint commissioned to find a suitable alloy replacement for silver. The other two are P5195 and P5340.
The obverse features a bust of Dr. Paul D. Merica and the reverse features his laboratory where the pieces were struck. The design was created by Gilroy Roberts and the hubs were created by the Medallic Art Company.
Examples are known as follow:
P5379 95% nickel, 5% silicon on a permalloy core of 79% nickel, 16% iron and 5% molybdenum with plain edge
P5380 95% nickel, 5% silicon on a permalloy core of 79% nickel, 16% iron and 5% molybdenum with reeded edge
P5381 95% nickel, 5% silicon (no core) with reeded edge
P5382 90% silver, 10% copper with reeded edge
Photo courtesy of Heritage.