Gemstones like precious opal are beautiful to look at and deceivingly complex. As you look at such gems from different angles ...

In sites stretching from Beijing, China, to Altamira, Spain, archaeologists have turned up remains of red clay dating back to ancient times, indicating how the color’s use—and significance—has endured ...

Each kind of commercial and emergency vehicle follows a certain color code or symbol. For instance, you will find a snake symbol on almost all ambulances, and the color of the school buses is always ...

The objects in the painting are brought together in a spectacular show at the Museum of Modern Art. It’s a marvel of detective work by the curators. By Roberta Smith The Museum of Modern Art’s latest ...