Here’s what you’ll learn when you read this story:

• Research into a Neolithic settlement called Motza revealed the earliest known use of dolomitic lime plaster.
• The Motza plaster predates the better-known Roman plaster by 8,000 years, rewriting the technological history of kilns and plaster creation.
• The craftspeople in Motza had separate kilns for dolomite lime and calcite lime, showing a true understanding of their differing properties.

Forget the Romans. When it comes to breaking ground on the technological application of dolomite-based plaster, all credit goes to the ancient inhabitants of Motza, in what’s now Israel. Dolomitic plaster—a stronger and more water-resistant plaster than typical calcitic plaster—historically gets credited to the Romans, but new research shows that 8,000 years earlier, the pre-pottery Neolithic craftspeople in Motza already possessed the technical know-how needed to burn dolomite for plaster floors.

Typically, plaster comes from calcite in limestone, but dolomite limestone is a sturdier option. Burning it down for use as plaster, though, isn’t simple. It requires a higher level of expertise at every step of preparation, according to a study published in the Journal of Archaeological Science that revealed the previously unknown history of Motza’s plaster.

The preventive archaeological excavations at Motza, which is roughly three miles from Jerusalem, were undertaken ahead of an upcoming highway project. During the dig, archaeologists found more than 100 plastered floors in ancient structures from roughly 7000 B.C.E. that offered the first clues about the Neolithic people’s expertise. As the Israel Antiquities Authority-led team investigated the site, they also discovered two kilns positioned side-by-side, one used exclusively for the burning of limestone and the other for dolomite. Already, 8,000 years before the Romans, the Motza people had the technical understanding to separate the two stones into differing kilns and to use specialized methods to transform each into plaster.

Since limestone is mostly calcium carbonate, while dolomite features calcium and magnesium carbonate, the temperature and mixture needed to make plaster differs for them both. The separate firing pits suggest Motza builders understood the different behaviors of the stones, so rather than just haphazardly tossing the rocks into kilns, they were differentiating them based on technical needs.

Dolomite plaster is by far the trickiest of the two types to create. It requires burning at a lower temperature and a very precisely calculated amount of water. Done properly, the result is a heartier plaster that’s also water-resistant. High-quality dolomite plaster is a rare find in the archaeological record due to the great degree of difficulty in producing it.

The researchers wrote the residents of Motza made plaster with a standard recipe, but they also began to “cleverly utilize local materials” along the way, including using dolomite both as an aggregate and as a binder, “despite technical difficulties.”

That technical understanding then translated to actual structures. The researchers wrote that the dolomite plaster—some of which still contained red pigment traces—was often used as a thick base layer for flooring, with the smoother calcitic plaster serving as an artistic layer over the top.

In another archaeological rarity, the researchers observed a product of the dolomite-lime cycle that still isn’t fully understood. Using infrared spectroscopy, X-ray diffraction, thermogravimetry, scanning electron microscopy, and light microscopy to analytically test the floors and plaster kiln remains, the archaeologists concluded the ancient craftspeople were able to make the plaster so well that tiny dolomite crystals reformed after the plaster’s creation.

“They may have successfully made dolomite plaster where dolomite is fully recrystallized along with the calcite,” the authors wrote, “something that to our knowledge has not been observed anywhere else.”