Tag: colored gemstones michigan
My goal, for the last three years, has been to become a graduate gemologist. I was the kid who had the rock collection and walked the beach looking for Petoskey stones. I am the adult who loves gemstones and jewelry. After years of teaching mathematics (another love of mine), the time seemed right to give gemology a chance. It’s been a wonderful and, at times, difficult journey. Gemology is not an easy science.
Gemology (or Gemmology) is the science dealing with natural and artificial gems and gemstones. It is classified as a geoscience, a branch of mineralogy. A gemologist studies the formation, localities, and physical properties of gemstones. He/she must be able to assess gemstones, using equipment and techniques to identify and evaluate the gem material.
I’m taking my classes through G.I.A. (Gemological Institute of America), which is based in Carlsbad, California. But there are plenty of places that offer gemology education. Some of the more well known schools are the Gemmological Association of Great Britain (GemA), the Canadian Institute of Gemmology (CGA), the Asian Institute of Gemological Sciences, and the Deutsche Gemmologische Gesellschaft (DGemG) in Idar-Oberstein, Germany. I don’t know a lot about the other schools, but I have been impressed with the education I’ve received at G.I.A.
A graduate gemologist diploma from G.I.A. means successful completion of three lab classes that teach you how to use the equipment and master the techniques needed to assess and identify diamonds and colored stones. There are also four reading courses that go over the history, localities, formation, crystal structures, and chemical/physical properties of diamonds and colored gemstones. Finally, there is a comprehensive gem identification course which requires both reading and lab work. During the course you are required to identify 500 gemstones. The course is designed to prepare you for a 20-stone exam which can be passed only if all 20 stones are correctly identified. You get five tries at the six-hour exam. If you don’t pass, there is an opportunity to do remedial work and try again.
Gemologists work in jewelry stores, wholesale gemstone companies, auction houses, insurance companies, and appraisal firms. If a gemologist wants to become an independent appraiser, additional education is needed. And all gemologists need to keep their skills updated by taking courses and being active members in organizations such as the American Gem Society. It’s a scientific job that often requires good people skills. So, tip your hat to those gemologists! They have worked hard to gain their title.
Is it hard to believe that something as common as sand or dust is made of, basically, the same ingredients as the most beautiful amethyst? Silica and oxygen are two of the most common elements on Earth, and they are the two needed to form quartz, a group of minerals which contains, among other gemstones, amethyst. What a gift that, sometimes, the simplest and most common ingredients make an awe-inspiring product.
The “Quartz Family” is a wide-ranging group. Amethyst is part of the large or single crystal strand of this group, along with citrine, smoky quartz, rock quartz (colorless quartz), and prasiolite (green quartz). These are the quartz gemstones that are likely to be faceted in order to refract light. They are more transparent, being cut from a single crystal. There are two main reasons why these gemstones are different hues. Trace elements such as iron can mingle with the silica and oxygen to influence the color. Heat and/or irradiation acting on the mineral can also change its color. Citrine, for example, is generally made by heat-treating pale amethyst.
Another branch of the quartz group is the microcrystalline strand. Gemstones like tiger’s eye and aventurine are aggregates of many, many small quartz crystals. These gemstones are generally translucent or opaque and are rarely faceted. You might see them carved into cabochons or made into beads. Colorless quartzite is an aggregate that is often dyed in various colors, sometimes to mimic other gemstones like jade.
Gemstones with cryptocrystalline structure have crystals too small to be seen without a powerful microscope. Chalcedony, agate, and chrysoprase fall into this strand. Chalcedony comes in various colors, both naturally and with man’s help. Chrome chalcedony is naturally green due to a trace element of chromium. But black onyx is actually chalcedony that has been dyed black. Chrysoprase, one of the most valuable gemstones in the quartz group, is a translucent apple-green due to the presence of nickel. These gemstones are sometimes faceted but usually are made into cabochons, beads or other carvings. Agate, a multi-colored banded gemstone, can be used to carve cameos.
Quartz comes from almost every corner of the globe. South America, North America, Australia, Africa, Asia, and even Europe all have deposits of quartz. Because it’s so plentiful, even in large pieces, quartz is generally affordable. We often think that the more expensive something is, the more beautiful it must be. But that’s just not true in the case of quartz!