Beryl over , and its dimensions were long and in diameter. The largest cut aquamarine gem is the Dom Pedro aquamarine, now housed in the Smithsonian Institution's National Museum of Natural History. The ancient Romans believed that aquamarine would protect against any dangers while travelling at sea, and that it provided energy and cured laziness. Emerald is green beryl, colored by trace amounts of chromium and sometimes vanadium. Most emeralds are highly included, so their brittleness (resistance to breakage) is classified as generally poor. The modern English word "emerald" comes via Middle English "Emeraude", imported from modern French via Old French
Geology of Zambia crystalline basement rock. These rocks are generally impermeable, but store water in 10 to 15 meter thick weathered regolith and fractures. Zambia has extensive natural resources, most famously the copper ore of the Roan Group, which gave rise to the Copperbelt region. Until the rapid decline in copper prices in the mid-1970s, copper mining formed the backbone of the economy of Zambia. Demand has picked up for copper, along with secondary production of cobalt. The country has deposits of iron, zinc, lead and tin, as well as small scale gemstone mining from basement rock. The Ndola area has emerald, aquamarine,