Trump loves shiny things. Really shiny. The shinier the better. Shiny shiny shiny.

Since Bill Clinton occupied the White House, the commemorative medallions known as challenge coins have been stately symbols of the presidency coveted by the military, law enforcement personnel and a small circle of collectors.

Then came Donald J. Trump.

His presidency has yielded more — and more elaborate — coins that are shinier, flashier and even bigger, setting off a boom for coin manufacturers, counterfeiters and collectors, with one official Trump challenge coin recently fetching $1,000 on eBay.

Among those produced in recent months by members of a White House military unit is a coin featuring Mr. Trump’s private Florida club, Mar-a-Lago, on the front, and the presidential seal, the White House and Air Force One on the back. Another has Pope Francis on one side and the president’s face set against the White House on the other.

Shiny. So shiny.

The car is a nice touch.

Outside ethics watchdogs say the “Make America Great Again” coins shouldn’t be distributed to military personnel — a traditional use of presidential challenge coins — since the military is supposed to be walled off from politics.

And those watchdogs warn that coins featuring Mr. Trump’s properties, such as Mar-a-Lago, should not be produced using government resources — including funds, work hours or even phone calls and emails — since federal ethics laws prohibit the use of public resources to promote private businesses.

The Mar-a-Lago coins are akin to “a metallic tourist brochure,” said Norman L. Eisen, a former ethics lawyer in President Barack Obama’s White House and the chairman of a watchdog group, Citizens for Responsibility and Ethics in Washington.

Killjoy.

After The New York Times inquired about the coins, agency personnel abruptly canceled plans for a coin featuring the president’s signature Trump Tower in Manhattan and his golf course in Bedminster, N.J.

Sad. They would have made such lovely metallic tourist brochures.

People who have traveled with Mr. Trump say he has become enthralled by challenge coins, attributing his interest to his appreciation for military traditions and might, as well as his attraction to gaudy displays of gilded excess. That fascination grew during the presidential campaign, when he would receive coins from law enforcement and military personnel whom he encountered at stops.

Shiny. Shiny, mama. Shiny shiny shiny shiny shiny shiny shiny shiny shiny.