What is a Reverse Proof Coin?

By GovMint :

A reverse proof coin is a unique coin finish that offers collectors a distinct twist on the traditional proof coin finish. In a reverse proof coin, the design elements that would typically appear frosted against a mirror-like background in a standard proof coin are reversed, meaning the background of the coin has a frosted, matte appearance, while the raised design features a polished, mirror-like finish. This reversal creates a striking visual effect that accentuates the intricacies of the coin's design in a captivating manner. Reverse proof coins are coveted by collectors for their novelty and unique aesthetic appeal.

Sources Used:

https://catalog.usmint.gov/faqs-faqcategory-products-programs/products-programs-reverse-proof-and-enhanced-reverse-proof.html?fdid=customer-service