Zirconium dioxide jewellery. Like diamond, cubic zirconia has a cubic crystal structure and a high index of refraction. Visually discerning a good quality cubic zirconia gem from a diamond is difficult, and most jewellers will have a thermal conductivity tester to identify cubic zirconia by its low thermal conductivity (diamond is a very good thermal conductor). This state of zirconia is commonly called "cubic zirconia", "CZ", or "zircon" by jewellers, but the last name is not chemically accurate. Zircon is actually the mineral name for naturally occurring zirconium silicate (ZrSiO). Zirconium dioxide Zirconium dioxide (), sometimes known as zirconia (not to be
Mineral industry of Africa Mineral industry of Africa The mineral industry of Africa is the largest mineral industries in the world. Africa is the second largest continent, with 30 million km² of land, which implies large quantities of resources. For many African countries, mineral exploration and production constitute significant parts of their economies and remain keys to economic growth. Africa is richly endowed with mineral reserves and ranks first or second in quantity of world reserves of bauxite, cobalt, industrial diamond, phosphate rock, platinum-group metals (PGM), vermiculite, and zirconium. Gold mining is Africa's main mining resource. The Central African Mining and Exploration Company (CAMEC),