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 ...

While investigating hackmanite, a natural wonder material, researchers found that it, in addition to two other minerals, can change their color upon exposure to UV radiation repeatedly without wearing ...