I sold several of these Martha Washington medallions a couple years ago. As I pack to move to my new home in Lake Oswego, I found one more. Its made of pewter and comes with a plastic stand marked US Mint.
The assay commission no longer meets and was disbanded a few years ago. The 1977 is the last year the medal was struck. In case you missed getting one of these before, I have one left you can have for $35 delivered in the USA.

Size is 3" x 2 3/8". Weight is about 4.3 ounces avoirdupois.