Tormaline: How Can one Mineral Have so Many Colors?

     As the title suggests the mineral tourmaline is very colorful. Tourmaline can be red, purple, blue, green, yellow, orange, colorless, or even black. All of these varieties of tourmaline are transparent, except for the black variety. Perhaps the most interesting thing about tourmaline is that one crystal can have more than one color. The most famous example of this multi-coloration is a variety of tourmaline that is green throughout one part of the crystal and red throughout the rest. This is called watermelon tourmaline. Surprisingly tourmaline crystals can exhibit more than two colors within a single crystal as well. The piece that I own (the one that is pictured) actually has three colors: red, green, and clear. Some tourmaline crystals have been found that contained fifteen sections of different colors or hues. And, like amethyst, tourmaline will sometimes appear to change color when it is viewed from different angles. If you are interested in minerals purely for their colorful properties, be glad that there's tourmaline!
     Many of the different varieties of tourmaline have different names as gemstones. Red or purple tourmaline is called rubellite, blue tourmaline is known as indicolite, the orange variety of the stone has been named dravite in honor of Drave, Australia; colorless tourmaline is known as achroite, and black tourmaline is called schorl. All of these, as well as yellow and green tourmaline, are used as gemstones except for schorl, which is not very popular. Even some of the multicolored crystals are cut for use as gems.
       Tourmaline has one of the strangest chemical makeups that I've ever seen. In one book I own tourmaline is described as a "complex borosilicate." A description that's a bit closer to the truth would be "very very complex borosilicate!" The English philosopher John Ruskin once said that tourmaline's chemical formula looked, "more like a medieval doctor's prescription than the making of a respectable mineral!" After you see the formula written out [Na (Mg,Fe,Al,Mn,Li)3Al6(BO3)3(Si6O18)(OH,F)] I think you'll agree with him!
       Tourmaline is definitely not an ordinary stone. It has an astounding range or color, can appear to change color when held at different angles, and can have several different colors present in just one crystal. How many other minerals can do that?
        Tourmaline is found in Brazil, Russia, Madagascar, Australia, and the southwestern United States. I wish that is was found everywhere so that everyone could have a piece of it because, like all of our Creator's artwork, it is truly something to marvel at!

Rhodonite: a Rose in a Rock

       Rhodonite is a pink-colored mineral that is usually found in a massive habit. When a mineral is said to have a massive habit that means that it forms in lumps with no distinct shape. Rhodonite is occasionally found in crystalline form, but the crystals are usually very fragile. Rhodonite is also known to form as stalactites on other rocks.
      Rhodonite is a somewhat popular gemstone these days. It is usually cut as a cabochon (a shape that resembles a lens) and I have noticed that it is usually set in silver. Pink and red rhodonites are used for jewelry, but samples with black lines of manganese oxide running through them are most popular. Rhodonite is also the state gemstone of Colorado where it can be found and is a popular stone for jewelers. Elsewhere in the nation the stone remains a little less popular because it is not well known.
     Despite its name rhodonite does not contain any of the element rhodium in its molecular makeup; rhodonite is a manganese silicate. The name actually derives from the Greek word rhodos, which means rose. The name refers to the rhodonite's pink color. One of the pieces that I have in my collection is filled with little silver speckles at its center. These might be silver or perhaps pure, leftover, manganese metal that did not react, but I do not know.
     The most prominent sources of rhodonite around the world include the Ukraine, the Australian state of New South Wales, and Colorado. It is an interesting material and I am glad to have a few samples in my collection.

Amethyst--the Tie-dyed Quartz

        Amethyst is a purple-colored variety of the mineral quartz. In pure form quartz (silicon dioxide) is colorless, but impurities can alter its color. The purple color of amethyst is thought to be the product of tiny amounts of iron impurities. Amethyst can also be dichroic, which means that its color can appear to change when it is viewed at different angles (certain inks, such as the one used on the American $20 bill, do this too) Amethyst often has tiny drops of liquid trapped within its crystal structure, as well. The technical term for anything that is trapped within a crystal is an inclusion. In the case of amethyst these liquid inclusions are often called "tiger stripes" because the look like the stripes on a tiger's fur. It is because of all of these color phenomena that I call it the "tie-dyed quartz."
      Like quartz amethyst often forms within natural gas pockets and geodes. Quartz is the most common mineral in the world and is found everywhere on earth, so amethyst could theoretically be found anywhere. However there are certain areas where the mineral is found in abundance, most notably Brazil and the Ukraine. I have personally never found any in nature, but I do have three clusters of amethyst and one geode that contains the purple mineral. I think that amethyst is a beautiful mineral because its color is so uncommon.