Copper is synthesized in massive stars and is present in the Earth's crust at a concentration of about 50 parts per million (ppm), where it occurs as native copper or in minerals such as the copper sulfides chalcopyrite and chalcocite, the copper carbonates azurite and malachite, and the copper(I) oxide mineral cuprite. The largest mass of elemental copper discovered weighed 420 tonnes and was found in 1857 on the Keweenaw Peninsula in Michigan, US. Native copper is a polycrystal, with the largest described single crystal measuring 4.4×3.2×3.2 cm. COUNT 5
QSN1 What is the concentration of copper in the earths crust. ANS1 50 parts per million QSN2 How large was the biggest find of copper? ANS2 420 tonnes QSN3 What year was the largest find of copper discovered? ANS3 1857 QSN4 How big is the largest copper crystal that has been found? ANS4 4.4×3.2×3.2 cm QSN5 Where was the largest mass of copper found? ANS5 Michigan, US