How do they form? * Why do they shine? * What sets value in a gem? * How can you spot a simulant or synthetic? * What creates a cat's eye or star in a gem? * How can you tell one red gemstone like a ruby, from another like a red garnet, or a piece of red glass? * Which gems are best for jewelry and why? * Where and how are gems mined? * How are they cut and polished? * What is the toughest gemstone? (No, it's not diamond!) * What the heck are these? * * * --->(You can find descriptions/explanations of these pictures at the bottom of this page)<--- Want to know more? Read on... Hello, I'm Barbara Smigel .....
If you're interested in learning about gemology from a scientific rather than from a commercial or artistic viewpoint, then you are in the right place (not that either art or commerce are unimportant or will be ignored, they just won't be our main focus.)
Below are a series of lessons that I've developed as part of a course that I teach at College of Southern Nevada, where I'm an Emeritus Professor. But you don't need to be a registered student to use these materials! As you go through the lectures and essays, you'll see references to text readings, homework assignments, self quizzes, discussions, and exams which are meant for the registered students only.
The down side is that you won't be able to access the actual course website and the materials posted there, unless you are a registered student. The up side is that you're welcome to freely browse the contents located here, and there are no tests, grades, or time schedules to worry about. I've posted a sample course syllabus for your information, but none of the rules, timelines, or expectations listed therein apply to you, the casual visitor or independent student. (See below if you would like to register, for credit, for a future course).
Web Lectures: These are the heart and soul of the course. As some of them are fairly lengthy, and all contain many pictures, depending on your connection speed, they may take a few minutes to download.
- Lesson 1: Basic Terms
- Lesson 2: Naming and Measuring Gems
- Lesson 3: Physical Properties of Gems
- Lesson 4: Optical Properties of Gems
- Lesson 5: Magnification and What it Reveals
- Lesson 6: Optical Phenomena in Gemstones
- Lesson 7: Gem Fashioning
- Lesson 8: Gem Enhancement
- Lesson 9: Synthetics and Simulants
- Lesson 10: Gem Formation
Web Essays: These short, to moderate length, one-topic, pictoral essays supplement and enrich the web lectures for each lesson.
- Lesson 1: Chrome Diopside, Jet, Benitoite, Aquamarine, Rock Crystal Quartz, Red Beryl, Coral, Ivory, Danburite
- Lesson 2: Labradorite, Mexican Opal, Chrysocolla Chalcedony, Morganite, Charoite, Tsavorite
- Lesson 3: Moldavite, Drusy Gems, Fire Agate, Nephrite, Botryoidal Gems, Hardness, Jadeite, Specific Gravity
- Lesson 4: Pyrite, Andalusite, Peridot, Ruby, Rhodocrosite, Dispersion, Tanzanite, Fluorite, Chrysoprase
- Lesson 5: Included Quartz, Rubellite Tourmaline
- Lesson 6: Aventurescent Gems, Chatoyance, Star Stones, Color Change Stones, Iridescent Gems, Cat'seye Stones
- Lesson 7: Considering Faceting, Less Common Organic Gems
- Lesson 8: Tanzanite, Zircon, Blue Topaz, Iolite, Oregon Sunstone, Spinel, Uvarovite Garnet
- Lesson 9: Synthetics, Simulants and Fakes, Assembled Stones, Natural Pearls, Freshwater Cultured Pearls, Saltwater Cultured Pearls
- Lesson 10: Sugilite, Malachite, Turquoise, Fossil Plants as Gems, Birthstones, Lapis Lazuli, Meteorites as Gems
Pronunication Guide: Alphabetically listed audio files with the correct pronunciation for some of the terms in the Web Lectures and Essays:
Bonus information: Survey of Gemstones A-Z (Very little lecturing here, just a bunch of cool pictures of common and rare gems with a few bullet points on each), downloads as Powerpoint presentation in pdf format.
Text Books and Reading Assignments: These are not absolutely necessary for enjoyment of the course materials, but as they are referred to in the lectures, some of you might like to have them. Each is available inexpensively from Amazon.com, and other, on and off-line, booksellers.
- The Smithsonian Handbook of Gemstones, Cally Hall & John Taylor, Dorling Kindersley, 2002
- Simon and Schuster's Guide to Gems and Precious Stones, Kennie Lyman, Editor, Simon and Schuster, 1986
- Lesson 1: Hall: pgs. 6-11, Lyman: pgs. 10-13 & 272
- Lesson 2: Hall: -- , Lyman: pg. 41
- Lesson 3: Hall: pgs. 16 - 19, Lyman: pgs. 34 - 37, 42 - 47 & 55
- Lesson 4: Hall: pgs. 20 - 22 & 38 - 47, Lyman: --
- Lesson 5: Hall: pgs. 24 - 25, Lyman: pgs. 52 - 55
- Lesson 6: Hall: pg. 23, Lyman: pgs. 112 - 115 & 222 - 229
- Lesson 7: Hall: pgs. 26 - 31, Lyman: pgs. 58 - 68
- Lesson 8: Hall: pg. 37, Lyman: ---
- Lesson 9: Hall: pgs. 34-37, Lyman: pgs. 316 - 328
- Lesson 10: Hall: pgs. 12 - 15, Lyman: pgs. 37 - 41
This course is offered at CSN, http://www.csn.edu/ as Geology 115, Introduction to Gemology, and is an ongoing offering through our Distance Education Department via the internet for anyone, regardless of their geographic location, (in the US or not).
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What are they? The leftmost picture is a magnification of a type of inclusion characteristic of peridot gemstones, particularly those from Arizona, they are called lily pads, although I must admit "flying saucers"comes to my mind. This picture is described and discussed in Lesson 5: "Magnification and What it Reveals". Secondly, we see part of the magnified surface of a rough diamond, the triangular markings, known as "trigons" are diagnostic to diamond. This image finds use in Lesson 5 and also in Lesson 8: "Synthetics and Simulants". Next we see a 10x magnified picture of the lid of a 1920's Art Deco cosmetic jar. It is covered with shagreen, which is a leather made from sharkskin -- an unusual, but valuable. organic material sometimes used in jewelry and ornamental items. You'll learn more about shagreen in the essay on Unusual Organics. Finally, you are seeing a view of a type of simulated emerald widely sold under the trade name "Soude" or sometimes "spinel triplet". It consists of two colorless layers of glass or white spinel with green glass or even green glue in between. In Lesson 8 we will see a view of this gem as it would appear in jewelry (perfectly uniformly green), and, as in this photo, immersed in water and photographed from the side revealing its "sandwich like"nature.