beryl

The emerald, Brazilian authorities say, was discovered in a beryl mine in the country in 2001 and later smuggled to the U.S.

If the quartz can’t scratch the specimen, it might be beryl or corundum, which are harder than quartz.

One of the mightiest of the stones on display at the museum is a four-foot-tall, 7,756-pound hunk of grayish-green rock called beryl, from which come emeralds as well as beryllium.

Oxford County, they learned, was a mining center famous for its tourmaline, quartz and beryl.

The Massachusetts couple became interested in the local mining history and bought a tract that included the Bumpus Mine, which had produced feldspar and the gemstone beryl.