New York and other cities see a climate fix in white paint, which is coating more rooftops as way to cool buildings and cut energy use. They may soon have another option: paint made of glass.

Scientists have created a glass paint that can bounce sunlight off metal roofs and keep them at air temperature. This is no minor feat. The sun can heat metal surfaces so much that playground slides or stadium bleachers can become too hot to use.

The new paint has another potential upside. Since it’s almost completely inorganic—a mixture of silica, the main ingredient in glass, and silicon rubber—it doesn’t degrade in ultraviolet light and can last much longer than typical polymer-based coatings.

“It’s almost like painting a rock