Lesson 19 - Lesson 19: Tools of the Trade Introduction In...

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Lesson 19: Tools of the Trade Introduction In the early parts of the course we looked at the "who's who" of the gem and jewellery world and also the "what's what" of magnificent gems. We learned about some fundamental science concepts (e.g., the interaction between light and a gem) and also looked at properties of diamonds, emeralds, rubies, and sapphires! We learned the concepts behind the differences between a clear sapphire and a diamond, and how we might confirm that a green gem is in fact emerald. But what tools do we use to extract this information from the gems and to allow us to answer our burning questions conclusively? In this section we'll learn about common tools used by gemologists, mineralogists, and geoscientists to test and reveal the properties of gems. If you don't feel confident that you have fully learned the concepts discussed in "Colour and Light", "Elements and Matter", and "Minerals", we encourage you to go back for a refresher to confirm just how the tools described here play their parts in those concepts. Our textbook covered much of the basic physical properties (e.g., SG, density, fluorescence) that are used to identify gems, and our Lesson on Colour and Light provided us with information on the optical properties that are commonly used to distinguish one gem from another. Essential readings and topics for this lesson in your textbook Topic Pages Physical properties and mineral identification 92 - 95 UV Fluorescence 160 - 161 Optional Resources Mineral Identification Key II , published by the Mineralogical Society of America. Basic Tools
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shops and rockhounding. Unaided eye Our most important and reliable tool is simply our eye, unaided and unhindered. It gives us immediate information about the colour of a stone, although that is not always diagnostic. A trained eye can estimate the dispersion of a stone, observe crystal habits, fractures, and cleavages, and identify characteristic inclusions and associated minerals. The eye also allows us to collect observations using other methods, and along with the brain facilitates the combined contextual interpretation of all our observations. For a little boost, hand lenses and magnifying glasses are often used to look at the finer details. Tweezers A simple tool, but necessary for anyone looking at minerals, gems or jewellery. A steady hand is tough to find, and even if you have one, the oils or sweat from your skin can alter the optical properties of the item at hand. Gemstone-specific tweezers also have a couple of adaptations to facilitate investigation including textured tips (for grasping stones), small groves along the end of the tips (for a better grip of stones along their girdle), and locking mechanisms (so you don't drop a stone!). Other gem specific tweezer tools are stone holders. They resemble a clicking pen with the point replaced with spring-loaded retractable prong claws and no stopping mechanism. They allow for a stone to be tightly held by more than two contact points, as with tweezers. Locking gem tweezers
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This note was uploaded on 11/18/2011 for the course EOSC 118 taught by Professor Daveturner during the Spring '10 term at The University of British Columbia.

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Lesson 19 - Lesson 19: Tools of the Trade Introduction In...

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