Editor’s Note: Jim Sullivan is the Senior Mineralogist for the Coeur d’Alene, Idaho, based Near Earth Exploration. To see more examples of minerals in their natural state, please visit his Etsy shop.
Where do Minerals Come From?
There is an old adage which states, “If it can’t be grown, it’s gotta be mined.” Nearly everyone has a familiarity with where many of their products come from. The gold in their necklace, “Oh, it came from a gold mine.” The diamonds in their rings, “Oh, it came from a diamond mine.” The Copper and Iron in their lives come obviously, from Copper and Iron mines.
But what is it exactly that is being mined? Gold and Copper occur in nature as their base elements, in nearly a pure state, Iron does not. Most of us have seen pictures of Gold veins in Quartz, and in some places, like the Upper Peninsula of Michigan, Copper occurs as nearly pure masses of the metal. Other metals, like Vanadium, Beryllium and Lead do not occur as pure elements. These elements are found as constituents of particular minerals and must not only be extracted from the earth, but extracted also from the mineral they are a part of.
What is a Mineral?
The traditional definition of a mineral is ‘an inorganic, naturally occurring solid with a crystalline structure and definite chemical composition.’ Many of us have seen Quartz crystals (Silicon Dioxide) the six-sided, pointed on top, familiar definition of ‘crystal’; or Pyrite crystals (Iron Sulphide) brass-yellow cubes often called ‘Fool’s Gold’. There are more than 4,800 different minerals recognized by modern science. It is from different minerals that we extract different elements for our use.
How we Use Them
Many minerals containing metals vital to our lives need work done to them before they are ‘usable’. Iron, for instance, only very rarely occurs as a native element in the crust of the earth, despite it being the primary constituent of the Earth’s core. The Iron we mine to make steel comes from the minerals Hematite and Magnetite. In these minerals the Iron atom has bonded with Oxygen atoms. At times, if the temperature and pressures are just right during the formation of the deposit, these minerals can form spectacular crystals. In the United States, there is a massive Iron deposit in north-east Minnesota where they mine the rock Taconite.
Taconite is a less pure form of Iron ore comprised of the minerals Hematite and Magnetite trapped in a variety of Quartz called Chert. While it may not be the highest grade of Iron ore, the deposit is tremendously large and the refining process is quite simple, which makes the rock feasible to mine in economic quantities.
Beryllium is a good metal to use as an example. It is quite the rare element in the crust. Estimates of between 2 and 6 parts per million exist on our planet (compare to Silicon, which is rather abundant at 270,000 parts per million in the crust). Not only is the metal quite important to the military and medical industries because of its inherent properties (it is very lightweight, invisible to X-rays, and terrifically strong), it also has use in its mineral state as an adornment. Many people wear Beryllium ore without even knowing it. Do you have an Aquamarine or Emerald in a piece of jewelry? These gemstones are the most pure form of the primary ore of Beryllium, the mineral group aptly named ‘Beryl’. Both Aquamarine and Emerald are both gem grade varieties of Beryl, as are the gems Morganite, Bixbite, Goshenite, and Heliodor. All share the same basic chemical composition,
but due to different elements included in the crystalline lattice, they reflect different wavelengths of light. Chromium gives Beryl a rich green color, we call those ‘Emeralds’, pure colorless Beryl is called Goshenite, red is Bixbite, yellow is Heliodor, and pink is Morganite. “Common Beryl” is the mineral used as Beryllium ore, and it occurs as greyish to greenish opaque crystals and masses. It has no use in the jewelry industry, but the metal can be alloyed with Aluminum or Copper which makes the resulting alloy several times stronger than the base metal alone.
The crystalline mineral form of minerals make for excellent teaching aids for geological sciences, metallurgy, and engineering purposes, and there are even people dedicated to developing collections of minerals, just as some people collect coins or baseball cards. The amazing variety of colors, shapes, compositions and locations from which these minerals come help to start many future Geologists on their career path, and the complexity of the aspects associated with minerals means that there is always something new and exciting to learn.
Quartz crystals from Washington, USA
Hematite crystals with Rutile crystals from Brazil
Common Beryl from North Carolina, USA
Gem grade Beryl, var. Aquamarine from Pakistan