Editor’s Note: This story originally appeared in On Balance, the ARTnews newsletter about the art market and beyond. Sign up here to receive it every Wednesday.

If you were asked to guess the artist behind the most expensive artwork on offer at Art Basel Miami Beach earlier this month, a few (male) artists’ names would likely come to mind: Jeff Koons, Gerhard Richter, and Andy Warhol would probably figure on the list.

Guess again: A 1979 untitled abstract work by Joan Mitchell, on offer from Chicago’s Gray Gallery, was tagged at $18.5 million, making it the priciest work on view at the Miami Beach Convention Center (beating out an $18 million Warhol sold by New York gallery Lévy Gorvy Dayan).

This year marks a century since the birth of the American painter, who spent much of her time in New York and France, where she died in 1992. Known for deeply expressive, lyrical abstractions, Mitchell was one of t...