The call came two decades ago, but I remember it well. A professor from the State Office for the Preservation of Monuments in Saxony told us that the Green Vault in Dresden was to be restored. Around 80 percent of the historic mirrors inside had been destroyed. For me as a child of the GDR, this collection of rare, world-class exhibits has great personal significance. The professor asked if I could make new mirrors with mercury according to the original process. “That’s crazy,” I thought.
We normally make mirror glass by spraying on silver nitrate—a process that’s modern and clean. For the Green Vault, everything was to be produced in the same way as in the 1720s: with a tin-mercury amalgam. This is a tricky process, and the heritage conservation department had not found anyone who could still master the technique.
It was the same for me—I started from scratch, researched in books that were two centuries old, set up a laboratory, and procured protective equipment. Then I worked on my first samples and had my blood tested regularly because of the contact with mercury.
This element is contradictory. It flows without wetting surfaces; it evaporates easily, although it is heavy; it shines, but does not give off any light. The steps of the process are the same as in the 18th century. Spread the tin foil on a marble plate and add a little mercury. Wait until the amalgam forms. Then frame the plate and flood it with a larger amount of mercury. The glass is then carefully slid onto this layer from the side. The thin layer of amalgam adheres to the glass, and the excess mercury runs off again. Every step demands its own pace; if you push too hard, you lose. But this creates a surface that no modern mirror can match. The reflectance is lower, the colors of the mirror image are true.
6,460 square feet of mirrors.
Today, the Green Vault once again has over 6.460 square feet (about 600 square meters) of mirrors. They don’t open up the space—rather, they encompass it. When I’m there, I can feel their effect: soft light, authentic colors. The history of the exhibited objects comes to the fore, and the mirrors set the stage for this.
It makes me proud to see my mercury mirrors in places that tell a story. In the Green Vault, but also here in the parade rooms of the Residenzschloss, I think of my first reaction: “Crazy.” Maybe it was—but it was worth it.”
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Scene of a spectacular art heist
It takes only minutes—and leaves damage of historic proportions. In the early hours of November 25, 2019, burglars break into Dresden’s Royal Palace, smash a display case in the Green Vault, and grab whatever they can. Twenty-one pieces of jewelry set with roughly 4,300 diamonds vanish in a precision-style heist. Insured value: at least €113.8 million.
What’s missing, however, is more than money. Crafted in the 18th century, the pieces are considered unique—their cultural value is almost impossible to quantify. Fears mount that the thieves might dismantle the treasures, sell the diamonds off one by one, and erase the historical context for good.
The case unfolds into a long-running crime drama: The trial of six defendants doesn’t begin until 2022. In December of that year, a large portion of the haul resurfaces, returned through attorneys. Convictions follow in 2023—five perpetrators receive prison sentences, one is acquitted.
What remains is a spectacular coup—and the sobering realization of how vulnerable even the best-guarded treasures are.
