These days, Tungsten jewelry is everywhere. You can easily find it at major stores such as Wal-Mart, and have your choice of fine (and some not so fine) online retailers. Not to mention, many actual jewelry stores do carry tungsten products. As you may have learned, Tungsten, due to its durability and characteristics, can also be found in many other things in our daily lives, such as light bulbs. Tungsten is used as filaments for light bulbs. However, not many people know where the tungsten that is easily found and available in stores actually comes from.
Tungsten makes up a very small portion of the Earth’s crust and is a very scarce metal. Tungsten makes up just a miniscule 1.1 parts per million of the Earth’s crust. Just to get an idea, other elements such as Iron (about 63,000 parts per million) and lead (about 10 parts per million) make up a larger portion of the Earth’s crust. Tungsten’s closest “relatives” in the periodic table are usually considered to be molybdenum and tin, which make up similar parts per million of the Earth’s crust: 1.1. and 2.2 respectively.
Although, it sounds very small in the grand scheme of the parts per million of the Earth’s crust, the Earth’s crust is enormous and therefore there is still plenty of Tungsten. However, it is never naturally found as a metal. Tungsten can only be found as a mineral, meaning it is found combined with other elements to form compounds. In fact, there are more than twenty tungsten minerals that can be found in nature, but only two of those are used to extract metal: scheelite and wolframite.
Wolframite is usually associated with a tin ore known as cassiterite that is usually found near granitic rocks. Wolframite is black-brown mineral and is one of the main sources for tungsten, as mentioned above. When found in its natural state, wolframite will contain varying levels of manganese tungstate and also iron tungstate. Depending on the composition of wolframite mineral, it will be called a different name. If the mineral contains more than 80% manganese tunsgstate is known as hubnerite, whereas if the mineral consists of more than 80% iron tungstate it will be known as ferberite.
Whereas Wolframite will be found in that black brown color, Scheelite varies in color from white to green. Also, under ultraviolet light, pure scheelite will glow. Unlike wolframite that will have manganese tungstate or iron tungstate, scheelite will consist of calcium tungstate.
Whether it is found as wolframite or scheelite, the tungsten metal can eventually be turned into a variety of things, including the tungsten carbide rings that are becoming increasingly popular.