Archaeologists Found a 10,000-Year-Old Plaster Technology Near Jerusalem That Should Not Have Existed Until Roman Times

Archaeologists have uncovered two shallow fire pits, side by side, that date back almost 9,000 years in the Judean Hills. One pit was used to burn limestone, while the other processed dolomite, a rock that requires precise temperature control to transform into a usable plaster.

These ancient burners operated without metal tools or written manuals, yet they solved a complex materials‑science problem that would not be documented for millennia.

Excavations at Motza, located roughly five kilometres west of Jerusalem, have revealed that Pre‑Pottery Neolithic B communities manufactured a dolomite‑based plaster that is tougher and more water‑resistant than conventional lime plaster. The findings, reported in the Journal of Archaeological Science, extend the earliest known use of pyrogenic dolomite in construction by about 8,000 years.

The previous benchmark for dolomite plaster was the Roman period, when the architect Vitruvius listed suitable stones for lime in the first century BC. Motza now pushes that invention back to the Neolithic.

A Neolithic Settlement with Plastered Floors

Large salvage excavations conducted between 2015 and 2021 ahead of highway construction uncovered a sprawling settlement dated to roughly 7100–6700 BC. More than 100 plastered floors were documented, ranging from well‑preserved surfaces stained with red pigment to later, thinner and more porous examples.

Typical lime plaster derives from limestone, which is rich in calcite. Dolomite, by contrast, contains both calcium and magnesium carbonate and can calcine at lower temperatures than calcite.

When processed correctly, dolomite yields a harder, more water‑resistant surface, but only if the firing temperature stays below about 900 °C and the slaking water is carefully managed. Any deviation can compromise the material, which explains why dolomitic lime was thought to appear much later in the archaeological record.

Separate Kilns, Separate Techniques

The most compelling evidence for intentional control comes from two shallow fire pits situated next to each other. Each pit measured between 1.5 and 2.6 metres across and about half a metre deep. One pit was dedicated to limestone, the other to dolomite, reflecting the need to treat each stone differently during calcination.

In some floor sections, dolomite appears as aggregate—crushed stone mixed into the plaster—while in others it functions as a binding component, integral to the floor’s structural integrity.

The research team applied infrared spectroscopy, X‑ray diffraction, thermogravimetry, scanning electron microscopy, and light microscopy to the kiln residues and plaster fragments. These analyses identified mineral phases, tracked heat‑induced transformations, and revealed microscopic textures.

Unexpectedly, the Motza plaster retained a high proportion of both dolomite and calcite, suggesting that some dolomite re‑crystallized after the stone was burned—a pattern not observed in later dolomitic lime productions.

Link to the Long‑Standing Dolomite Puzzle

The discovery touches on the broader “dolomite problem,” a geological conundrum describing the difficulty of forming dolomite under normal laboratory conditions despite its abundance in ancient rocks.

A plaster that appears to complete a full dolomite‑lime cycle—re‑forming dolomite after decarbonisation—offers a rare experimental model for scientists probing this mystery.

The authors propose that the Motza artisans possessed a lost technology capable of executing a complete dolomite‑lime cycle, analogous to the well‑understood calcite‑lime cycle.

Craft Knowledge Preserved in Stone

The plastered floors at Motza capture decisions made by a community that left no written records. Their expertise—selecting appropriate stones, maintaining a narrow temperature window, controlling water content, and shaping a durable surface—must have been transmitted through hands‑on learning within a disciplined tradition.