The German Town with Billions of Hidden Diamonds
Nördlingen, a quaint town in southern Germany, conceals a dazzling secret: its structures are embedded with millions of tiny diamonds. Experts estimate that the region and its surroundings hold approximately 72,000 tons of these precious stones.
Nestled within a crater, Nördlingen’s charm is evident in its medieval architecture, including the striking St. Georgs-Kirche church with its towering spire, set against the backdrop of red-tiled roofs. However, what truly sets Nördlingen apart are the microscopic diamonds interspersed throughout its buildings. These diamonds are the remnants of an asteroid impact that occurred around 15 million years ago.
The impact created the Nördlingen Ries crater, a depression spanning over 14 kilometers, where the town of Nördlingen now stands. This colossal event produced suevite, a type of impact rock composed of angular fragments, including glass, crystals, and diamonds. The extreme pressure from the impact—estimated at around 60 GPa—transformed graphite-bearing gneiss rocks in the region into diamonds.
Photo credit: The town of Nördlingen (YouTube screenshot).
Gisela Pösges, a geologist and deputy director of the Ries Crater Museum in Nördlingen, explains, "We believe the asteroid was a stony body with a mass of about three billion tons. The asteroid was roughly the size of Nördlingen, with a diameter of approximately one kilometer."
For Centuries, Locals Mistook the Crater's Origin
The history of Nördlingen dates back to 898 AD, when the first settlers began constructing the town. During the Middle Ages, they built the city’s defensive walls, which remain remarkably intact. (Nördlingen is one of the few German cities whose fortifications have withstood numerous historical conflicts, including the Thirty Years' War.) Builders utilized the most accessible material at the time: pieces of suevite.
"Our church, St. Georgs, is constructed from suevite and contains roughly 5,000 carats of diamonds. However, these diamonds are so minuscule— the largest measuring just 0.3 mm—that they hold no economic value, only scientific interest. They are visible only under a microscope," Pösges notes.
For many years, locals did not realize the rocks used in construction originated from an asteroid impact. They long believed the crater was volcanic in origin. It wasn’t until the 1960s that geologist Eugene Shoemaker identified the depression as the result of an asteroid collision. Subsequent research revealed diamonds within the Ries Crater rocks, leading to the estimation of more than 72,000 tons of diamonds in the area.
Today, Nördlingen attracts visitors from around the world eager to explore this diamond-rich town. The Ries Crater Museum offers guided tours and exhibits specimens from the Ries Crater as well as other impact sites globally. Noteworthy displays include a sample of moon rock from Apollo 16, and Apollo 14 and 17 astronauts, such as Alan Shepard and Gene Cernan, trained here in August 1970.
While other German cities like Munich, Augsburg, Leipzig, and Berlin also feature buildings made of suevite, Nördlingen stands out for its unparalleled abundance of this unique rock. Indeed, it is a true diamond in the rough.
