We've spent years searching for a substitute for the key ingredient in cement. We've found the Holy Grail: basalt

Researchers at UC Santa Barbara and Brimstone Energy say basalt and other calcium-rich rocks could replace limestone in cement production.

The approach could sharply cut energy use and CO2 emissions, addressing one of the world’s biggest industrial sources of climate pollution.

The findings, published in Nature, point to a potential path for lower-carbon Portland cement.

But widespread adoption would still face logistical and economic hurdles in the cement industry.