While investigating hackmanite, researchers found that it can change color upon exposure to UV radiation repeatedly without wearing out. The results show that the inexpensive hackmanite, which is easy ...

Christian Lacroix’s “Gold-Gotha” ensemble and reliquary cross boasts a riot of gemstones. It’s on display at the Metropolitan Museum of Art in New York until October. Others are often clear. Quartz, ...

Collectors prize the copper mineral linarite for its intense blue color, but specimens with crystals large enough to truly show off this hue are rare. Linarite, which also contains lead, typically ...