Zircon, a Source of Exotic Metals and a Source of Delight

    
     Zircon is a mineral that receives its name from the Arabic word zagrum, which is derived from the Persian word for “gold colored”. Indeed, some zircon is honey-brown in color, but light blue, light green, yellow-green, blue, and clear varieties are also common. Zircon crystals are tetragonal, but many zircon samples are found as broken pieces, water worn pebbles, and large stepped crystals. A stepped crystal is a crystal that exhibits different layers that extend further than one another like a tiny staircase. Zircon crystals can also be damaged by the decay of tiny amounts of the radioactive metals thorium and uranium that are found within them. Zircon crystals that have been damaged by radioactive decay are said to have a metamict structure. Metamict zircons are also known as “low” zircons.
     Zircons also display some curious optical properties. Colorless zircons can exhibit a fire more brilliant than that of a diamond and some zircons will also reflect light in such a way as to display a rainbow-colored flash within them. The color of a zircon can be changed by heating it and zircon can sometimes display what is called mineral fluorescence. Minerals that display mineral fluorescence (which are called fluorescent minerals) actually appear to change color and glow beneath an ultraviolet or black light and will even glow! I have personally seen my own sample of zircon become pink and glow under an ultraviolet light. There are a great many minerals that possess interesting optical properties, but it is safe to assume that zircon just might have out-classed all of them!
     Zircon is also a very useful stone. Zircon has been used as a gemstone for a great deal of time (it has been used in India for centuries) Colorless zircon can be used to imitate diamonds, but zircons can be distinguished from diamonds by their more brilliant fire, and the fact that zircons will chip and scratch while diamonds will not. Zircon also has a number of industrial and technological uses. Great amounts of zircon can be used to make ceramics, firebricks, and molds for metal casting. The metal zirconium was discovered within (and named for) zircon and the stone serves as the chief ore of zirconium today. Zircon also serves as a source of hafnium and thorium as well. Zirconia (zirconium oxide) can be extracted from zircon. Zirconia can be used to make cubic zirconia, which is used to imitate diamonds.
     Zircon has been mined in Sri Lanka for about two thousand years. It is also found in Myanmar, Thailand, Cambodia, Vietnam, Brazil, Nigeria, France, the Australian state of Tasmania, and the American states of Florida and Georgia. Zircon is both an ore stone and a gemstone as well as an interesting collection piece. It ranks among the most interesting of minerals in the scientific respect in my opinion.