Sand is ground with flower of natron, till the mixture is as fine as flour ... Thus the copper and sand heating together by the intensity of the fire, impart to each other their different qualities, ...
Archaeologists excavating near the Colosseum found a rare chunk of Egyptian blue pigment dating back about 2,000 years. Photo from Simona Murrone and the Colosseum Archaeological Park Across the ...
Flowers feed pollinators, conserve soil, purify water, and even remove toxins from the air. But the thing many of us adore the most about these astonishing plants is their beauty, and simply admiring ...