Post #318,262
12/7/09 8:41:04 PM
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Diamonds are valuable because they are expensive.
The look isn't the thing.
A diamond is a pretty boring gem, really. And the more perfect, the more boring. Until you get to the ridiculously large, all a diamond has going for it is the message "somebody spent a pile of money on me".
At $2.00/carat, glass is more romantic.
This from a guy who's ring has a stone on it he can't identify, that he found in the sand in the Sahara.
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Post #318,272
12/8/09 1:32:14 AM
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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?
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Drew
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Post #318,273
12/8/09 2:40:19 AM
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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.
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Post #318,287
12/8/09 11:12:19 AM
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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.
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Drew
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Post #318,288
12/8/09 11:37:43 AM
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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.
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Post #318,290
12/8/09 11:44:30 AM
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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
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Post #318,291
12/8/09 11:48:21 AM
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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.
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Drew
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Post #318,297
12/8/09 12:48:14 PM
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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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