Identifying minerals blends careful observation with dependable tests that reveal each specimen’s unique signature. Geologists examine hardness, streak, luster, cleavage, and crystal habit to tell ...

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 ...

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 ...

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. Subscribe to read this story ad-free Get ...