A watercolor by Hilma af Klint that has not been publicly seen since 1988 is now for sale at CFHill, a Swedish art advisory specializing in private sales and consignments. The delicate work will be on view starting April 29 at the Stockholm gallery as part of an exhibition that also includes work by Andy Warhol and Marc Chagall.

The 1930 watercolor, titled Eldslågor (Fiery Flames), sold at auction for $2,000 to a private bidder in 1988, a time when the Swedish painter’s work was still relatively unknown. The work is now estimated to sell for between $300,000 and $500,000.

“This is a very dramatic composition, which features a burning heart in a rocky landscape. It lends itself immediately to interpretation as a symbolic self-portrait,” says Michael Storåkers, head of contemporary art at CFHill. “This heart is a lonely one, too, but has a more triumphant, fiery expression.”

The work is one of two watercolors that Klint gave as a gift to a pair of younger female textile artists, Elsa and Magda Jerud, sisters whom she admired and were part of the Anthroposophical Society with her. The whereabouts of the second watercolor is unknown. A similarly-sized watercolor dated to 1931 sold last fall at a Swedish auction for $168,000, excluding buyer’s premiums, according to the Artnet Price Database.

“Our painting is simply a stronger piece, there is no doubt about it,” says a spokesperson for CFHill, adding that some experts recommended a pricetag as high as $1 million for Eldslågor. “It’s much more abstract, more like the works from this period exhibited at thte Guggenheim by Hilma af Klint, and still more intimate. Exactly what you are looking for when it comes to work from the 1930s, especially with the burning heart in the picture, seen as a potential self-portrait.”

The work will be included in the artist’s catalogue raisonné currently being produced by the Hilma af Klint Foundation.

The avant-garde artist who was certainly under-appreciated in her lifetime was the subject of a major retrospective at Guggenheim last year that received critical acclaim and broke the attendance record for the New York institution. The vast majority of the artist’s work is owned by the Hilma af Klint foundation, and the relatively few works in private hands rarely make it to auction.

Eldslågor will be exhibited in a show called “Ten by Ten,” which opens begins April 29 and runs through June 6. The group show covers 10 masters over multiple generations, geographies, and materials. Viewings are available by private booking only.