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Gemstones, Minerals & Fossils
Gemstones and Minerals
Gemstone Identification
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<blockquote data-quote="R_G_Bargy" data-source="post: 10195" data-attributes="member: 193"><p>I'll try and explain best I can. I use a small cardboard box about 150mm(6") square with one side removed, leaving 5 side intact. Using 2 cheap polarizing lenses, I cut a hole to fit them firmly in opposite sides of the box. Keeping them in line so when a light is shone though one it will also go through the other. With the light (a torch or the like) placed facing up, put the box on top with a lens in the center. Now look from above rotate the top lens and you will see it go from light to dark as the 2 polarizes go into opposite directions. With them placed so they are not letting any light through, you take a stone hold it with your finger tips and hold it mid way between the lenses. Rotate the stone around horizontally. If it's double refractive it will go light and dark as it's rotated, nothing happens to a single refractive stone. With a zircon it has one direction of single refraction. One needs to find this if the stone is to be cut, cause if a stone is cut in a direction of double refraction the facets are doubled and the stone will look fuzzy. If I can find where I put mine I'll put up a photo. Hopefully this is as clear as mud <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite7" alt=":p" title="Stick Out Tongue :p" loading="lazy" data-shortname=":p" /></p></blockquote><p></p>
[QUOTE="R_G_Bargy, post: 10195, member: 193"] I'll try and explain best I can. I use a small cardboard box about 150mm(6") square with one side removed, leaving 5 side intact. Using 2 cheap polarizing lenses, I cut a hole to fit them firmly in opposite sides of the box. Keeping them in line so when a light is shone though one it will also go through the other. With the light (a torch or the like) placed facing up, put the box on top with a lens in the center. Now look from above rotate the top lens and you will see it go from light to dark as the 2 polarizes go into opposite directions. With them placed so they are not letting any light through, you take a stone hold it with your finger tips and hold it mid way between the lenses. Rotate the stone around horizontally. If it's double refractive it will go light and dark as it's rotated, nothing happens to a single refractive stone. With a zircon it has one direction of single refraction. One needs to find this if the stone is to be cut, cause if a stone is cut in a direction of double refraction the facets are doubled and the stone will look fuzzy. If I can find where I put mine I'll put up a photo. Hopefully this is as clear as mud :P [/QUOTE]
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Gemstones, Minerals & Fossils
Gemstones and Minerals
Gemstone Identification
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