Naive question

Post #318,272 by drook 12/8/09 1:32:14 AM Reply	Naive question I thought (part of) the reason diamonds are valued as a gemstone is because of the way they reflect and refract light when cut well. Granted, those big hunks of crystal people hang from their rear-view mirrors do that, too. But are diamonds objectively better than other clear crystals at reflecting and refracting light? -- Drew
Post #318,273 by Andrew Grygus 12/8/09 2:40:19 AM Reply	The short answer is "yes". The refraction of diamonds makes them very brilliant - if cut in a very precise way at the proper angles - nothing else like it. A few crystals get close to the ballpark but not quite in it. Of course manufactured diamonds do just as well as natural ones, with fewer flaws.
Post #318,287 by drook 12/8/09 11:12:19 AM Reply	That's what I suspected, but ... I don't know if I've ever heard that from someone who wasn't paid by DeBeers. But if it's true, then diamonds in jewelry are still better than a random piece of glass of the same shape. How much better is a good question, but not three months' salary worth. -- Drew
Post #318,288 by crazy 12/8/09 11:37:43 AM Reply	Wanna give me an education? Buzzwords, web pointers I can believe, etc. If I'm going to go in and make a deal, at least i should know what I'm negotiating for. Keep in mind the setting will obscure it a bit, only the top of the diamond will be seen since there is a white gold collar around the top.
Post #318,290 by boxley 12/8/09 11:44:30 AM Reply	go here, this is a respectable outfit http://gia4cs.gia.ed...54CFQwJswodjmWesQ but a little like having an MSCIE, different practitioners vary. At least the general stuff is there
Post #318,291 by drook 12/8/09 11:48:21 AM Reply	It still needs to be clear Light goes in the visible face, bounces around, comes back out different angles and different colors. If you've got an occlusion in the middle, the light stops there and doesn't come back out. That why, unlike opaque stones like opal, you don't need just one good face -- it has to be good all the way through. -- Drew
Post #318,297 by Another Scott 12/8/09 12:48:14 PM Reply	Better? Dunno. As Andrew says, diamond has a pretty high refractive index which gives lots of fire and color when the light is refracted. Here's a pretty good page on diamond properties: http://nature.berkel...//wisc/Lect6.html Diamond (C) Refractive Index = 2.42 Lead Glass (SiO2+PbOx) Refractive Index ~ 1.70 http://en.wikipedia.org/wiki/Lead_glass Cubic Zirconia (ZrO2) Refractive Index = 2.15Â2.18 http://en.wikipedia....ki/Cubic_zirconia Moissanite (Silicon Carbide) Refractive Index = 2.65-2.69 http://en.wikipedia....n_carbide#Jewelry The angles of the facets would need to be adjusted as the refractive index changes. There are other differences in the materials that affect how the light is scattered (e.g. birefringence). HTH a little. Cheers, Scott.

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