The town ‘laid’ 72,000 tons of diamonds

The small town of Nördlingen is famous among tourists because diamonds are present almost everywhere.

Nördlingen, a small town in the Bavarian region of southern Germany, attracts tourists by its nickname “diamond town”. Scientists estimate the amount of diamonds here is about 72,000 tons.

The appearance of diamonds originated from a meteorite impact about 15 million years ago, creating the Nördlingen Ries sinkhole (or Ries crater) with a diameter of more than 14 km. This is also the location of the town of Nördlingen today.

People in the town did not know about the existence of huge diamonds until the 1960s when two American geologists – Eugene Shoemaker and Edward Chao – came to survey.

Initially, local residents thought the Nördlinger Ries crater was the result of a volcanic eruption. However, Shoemaker and Chao suspect the crater was created by an asteroid colliding with Earth.

As soon as they visited and noticed that the church’s walls were dotted with tiny clusters of diamonds, they knew the hypothesis was correct.

Extremely powerful impacts from space create suevite – a rock containing angular debris including glass, crystals and diamonds. Under an estimated pressure of up to 60 GPa from the explosion, the graphite-bearing gneiss in the area was structurally altered and formed diamonds.

In 898, the first residents began to settle and establish the town of Nördlingen. In the Middle Ages, they built a protective wall surrounding the town – a structure that still exists intact today after many wars. To build houses and public works, builders at that time exploited the easiest to find local material: suevite stone.

For centuries, local people did not know that the stones used to build their houses contained diamonds.

Church of St. Georgs, the town’s famous structure, is built entirely of suevite stone and contains about 5,000 carats of diamonds. However, their size is extremely small – the largest pellet is only 0.3 mm – so they have no economic value.

“You can only observe them under a microscope,” said Gisela Pösges, geologist and Deputy Director of the Ries Crater Museum in Nördlingen.