Giant Gemstone


GLORIOUS GREEN: High-quality emeralds are rarer than diamonds.

Miners in the African country of Zambia recently made a dazzling discovery: a massive emerald weighing more than 1 kilogram (2.2 pounds). Most emeralds uncovered by miners are smaller than a paper clip. This one is as big as a person’s hand!

Emeralds are rare and valuable minerals often used in jewelry. They form as elements are heated and pressed together in Earth’s crust, or outer layer. The gemstone’s striking green hue comes from tiny amounts of chromium (Cr) or vanadium (V) that become trapped inside the mineral as it forms.

The huge emerald is one of the largest ever found on Earth. It probably took hundreds of millions of years to grow to its impressive size, says Alisha Clark, a geologist at the University of Colorado, Boulder.