| In gemstone identification, you have to first of all | | | | measurable physical and optical properties of our |
| ask your self: to what extent you intend going on | | | | gems. Next they devised instruments to measure |
| this (gemstone collection). | | | | these properties. There was a long process of |
| Now, there are two kinds of gem identification | | | | systematically measuring and recording these |
| tasks: determinative and confirmative. | | | | properties so they could be looked up. (Though |
| Determinative ID is when someone hands you a | | | | well established, this is actually an ongoing |
| rough piece of rock and asks what it is. | | | | process.) Eventually all this got put together into |
| Confirmative identification is when someone wants | | | | methods that could be used by people without |
| to sell you a stone - usually already cut - and you | | | | extensive scientific backgrounds or large and |
| want to confirm that the gem is as advertised. | | | | expensive laboratory equipment. |
| Determinative identification skills may take many | | | | ... That is not to say that it doesn't require |
| years to develop, and may involve the use of an | | | | substantial education to identify gems. It is a large |
| array of expensive equipment for measuring | | | | and complex subject that is continuing to increase |
| everything from density to various optical | | | | in complexity as new gems are discovered and |
| properties or even thermal conductance. | | | | new ones are created in the laboratory. However, |
| Confirmative identification of gems is much easier | | | | one doesn't need a degree in chemistry or |
| to learn and may often be accomplished without | | | | physics to simply measure the properties of our |
| any tools at all other than your eyes. | | | | gems. The most esoteric part was discovering |
| Gemology has been defined as the "scientific | | | | those properties and creating the tools to |
| study of gemstones" There may be investors | | | | measure them. |
| whose only interest is in the value of the stones, | | | | Finally, I would like to share a simple method of |
| but if they ever need to distinguish one gem | | | | gem identification with you: "the Hodgkinson |
| from another, they are dealing with science. It is | | | | method of gem identification" - Its the dirty |
| nearly almost impossible to remove science from | | | | version though - after Alan Hodgkinson. All you |
| gemstone identification! | | | | need are your eyes and some clean hands. Pick |
| There are several different categories of | | | | up a stone in question and hold it up very close to |
| gemologist - jewelers, goldsmiths, lapidary, | | | | your eye so that you can look into the table. You |
| faceters, gem scientist. All these people identify | | | | must hold it very close without touching - almost |
| gemstones for various reasons and they use | | | | like inserting a contact lens, but again not touching. |
| several different techniques in order to achieve | | | | Look literally through the stone at a distant |
| this. | | | | source of light such as a lamp or light bulb. You will |
| Some simple tests that could help you identify | | | | see a number of reflections of the distant light |
| gemstones include: Scratch tests, where the | | | | source as they bounce around within the stone. |
| unknown is scratched by various substances, will | | | | Roll the stone around its axis and tilt it slightly |
| determine its hardness. Other useful tests are the | | | | while watching the reflections. Due to the |
| reaction to acids and the flame of a blow torch. | | | | refractive properties of gemstones, each |
| These are categorized as destructive tests and | | | | reflection will to some extent appear as a small |
| are obviously inappropriate for cut gems. | | | | rainbow. This is a single one of those rainbows as |
| It has been said and written that: For centuries it | | | | it appears looking through a spinel at the filament |
| was the lapidary who was in a position to most | | | | of a clear light bulb about 6 feet away: |
| easily recognize the differences in like appearing | | | | Depending on the gem material in question, that |
| gems. During the cutting process gems get | | | | rainbow will have varying properties. If the gem is |
| viewed intently, a perspective that no other | | | | doubly refractive you are likely to see doubled or |
| gemologist has. Identifying inclusions are given a | | | | ghosted (rainbow) images. Because the gem may |
| lot of attention, then as many as possible | | | | be cut in any orientation with respect to the |
| removed. Differences in hardness are readily | | | | crystal structure (which is responsible for these |
| apparent when cutting and polishing, as are other | | | | phenomenon) you may have to examine the |
| characteristics. | | | | stone from a variety of angles to be sure |
| ... A method needed to be devised where cut | | | | whether it is doubly refractive OR NOT. |
| gems could be identified without damage. To this | | | | Hope you find some of these exciting and not |
| end scientists began to first, identify the | | | | boring... |