The colors—oxidized, layered, blended without visible separation—are not painted on. They are not applied with a brush. They emerge from the clay itself through a process that has never been fully disclosed to the outside world, and that, by all accounts, cannot be replicated by any contemporary method. The technique is so labor-intensive, one expert noted, that “nobody would even start” trying to duplicate it today.

The piece in question—approximately 18 inches tall, dated to the 1880s or 1890s, priced at $2,800 with a replaced cap and a wooden base decorated in the style of the pottery—is a representative example of what has made Zsolnay one of the most collected and studied names in the history of European ceramics.

The Factory and the Family

The Zsolnay Porcelain Manufactory was founded in 1853 by Miklós Zsolnay in Pécs, Hungary, then part of the Austro-Hungarian Empire. It was his son Vilmos who transformed it from a regional stoneware producer into one of the most celebrated ceramics manufacturers in the world. Under Vilmos’s direction, the factory began exhibiting at the major international fairs that shaped taste and commerce in the second half of the nineteenth century. At the 1873 Vienna World’s Fair, Zsolnay took home a Silver Medal. At the 1878 Paris World’s Fair, the judges awarded the company a Grand Prix—the exhibition’s highest honor—for its high-fire glazed porcelain-faience.

Vilmos Zsolnay was, by all accounts, a relentless experimenter. He was drawn early to the glazed ceramics of ancient China and to the intricate surface traditions of Islamic and Iznik pottery, and he spent years attempting to develop equivalent techniques in his own factory. His daughter Júlia contributed Persian and Hungarian folk-influenced designs; his collaborators included chemist Vince Wartha and artist Lajos Petrik. It was this team that, in the early 1890s, created the technique that would define Zsolnay’s legacy.

What Eosin Is

Eosin—pronounced roughly “EE-oh-sin”—takes its name from Eos, the Greek goddess of dawn, a reference to the luminous, color-shifting quality of the glaze. Introduced commercially by Zsolnay in 1893, it produces a surface that appears simultaneously metallic and iridescent, with colors that shift depending on the angle of light. The most common eosin colors are green-gold, red, blue, violet, and purple, but the full palette is wide, and the most prized pieces combine multiple colors in a single piece.

The technical secret at the heart of eosin remains closely guarded by the manufactory—compared, in its protectedness, to the formula for Coca-Cola or the recipe for a legendary liqueur. What is known is that a substance is applied to the glazed surface and then partly burned away in the kiln, leaving behind the characteristic metallic sheen. The oxides that produce the colors are not painted; they are deposited through the firing process itself, which is why, as the observers at the Los Angeles Pottery Show noted, there are no visible separations between the color zones. The colors simply exist in the clay, impossibly blended, with no apparent technique to explain them.

For collectors, the value hierarchy within eosin is well established: pieces from around 1900 in multiple glaze colors are at the top of the market. A single-color eosin piece has real value; a comparable piece with two, three, or four eosin colors present can be worth many times more. Condition and form number are also critical: Zsolnay pieces are typically stamped with an incised form number that allows dating—any number below 5,675 predates the twentieth century, while anything above 9,140 was made after 1940.

Eosin at Auction: What the Numbers Say

The secondary market for Zsolnay eosin has been active at major auction houses over the past two decades, with results ranging widely depending on date, glaze complexity, form, and condition.

At Sotheby’s in May 2006, a major eosin vase realized $41,500. At Christie’s in April 2010, a large eosin piece sold for $24,400. Three eosin vases offered at Christie’s New York in December 2014 brought $60,000, $15,000, and $15,000 respectively. A Zsolnay eosin vase with twin elephant-head handles and stylized fish decoration, attributed to designer Nagy Mihály and dating to around 1905, sold for $5,500 at Shapiro Auctions in July 2020. A comparable vase sold at Roseberys London for $9,700.

Market data compiled by Invaluable places the general range for Zsolnay ceramics at auction between $400 and $60,000, with price determined primarily by date, number of eosin glaze colors present, form, and condition. Pieces from around 1900 with multiple glaze colors represent the upper end of the category. Rago Arts, Lyon & Turnbull, Quittenbaum, Bonhams, and Phillips have all offered Zsolnay eosin pieces in recent years.

Pyrogranite: The Other Innovation

Eosin is Zsolnay’s most famous contribution to decorative arts, but the factory’s other major invention—pyrogranite—is arguably more visible. Introduced in 1886, pyrogranite is a high-fire ceramic material that is acid-resistant, frost-resistant, and durable enough for exterior architectural use. The Zsolnay tiles on the roof of Budapest’s Museum of Applied Arts, the Hungarian Parliament Building, the Matthias Church, the Gellért Baths, and dozens of other landmark buildings are pyrogranite—color still vivid after more than a century of exposure to weather and pollution. Leading architects of the Hungarian Art Nouveau movement, including Ödön Lechner and Mikos Ybl, specified Zsolnay ceramics as a matter of course.

The Piece at the Show

The vase that George of Fullerton was examining dates to the era in which Zsolnay was at its most innovative—the 1880s and ’90s, when Vilmos was still alive and the factory was still privately controlled, before the disruptions of the First World War curtailed production and the nationalization of 1948 eventually stripped the Zsolnay name from the factory entirely for decades.

The colors in the piece—oxide-based, deposited from the air during firing rather than applied by hand—are exactly what those standing around it said they were: impossible to explain in conventional craft terms, and impossible to duplicate. Every color is separated from every other without visible demarcation. The blending is seamless in a way that contemporary techniques simply do not produce.

The piece is priced at $2,800, which, given the auction record for comparable Zsolnay eosin work at major houses, places it well within the accessible range of the category. Condition notes include a replaced cap and a wooden base decorated to match the pottery—factors a buyer would weigh against the quality of the eosin surface, which by all accounts is the thing that matters most.

For anyone unfamiliar with Zsolnay and wondering where to start, the standard reference is Zsolnay Art Pottery: The Gyugyi Collection, which documents forms, designer attributions, and glaze types in detail. The factory’s own archive, maintained in Pécs, holds records of more than 3,000 distinct designs logged between 1898 and 1914 alone.

A Footnote in Miniature

George also sold a miniature ceramic typewriter at the show. The piece, about the size of a playing card and approximately three inches tall, was rendered in black with white highlights replicating a typewriter’s keys and details. It dates to the early 1900s—approximately 1905 to 1910, based on the typewriter style depicted—and was likely produced as a promotional gift for a typewriter company to give to clients or retailers. Originally priced at $450, it sold at the show for $350.