cubic zirconia

[don_willard]

In looking into other synthetics, I ran across a site that advertises its own diamond supposed lookalike, a very expensive one, and this site said that (their enemy) cubic zirconia had “a bad reputation because of its tendency to change color.” I had never heard of this. I know there are very sharply double cut cubic zirconia gems that are very clear and many colored ones, but the only negative comments I’ve heard about this material is that it is only about 8 in hardness, it is poorly cut more often than not, and it is so affordable that nobody but a collector and aesthete like me who likes it for itself wants it. Has anyone had any experiences of this sparkling and sending off color flashes-more-than-diamond changing color?

[Duck_Duck_Goose]

Well, evidently there’s a kind of CZ called “color change CZ”, but I can’t find anything on how it’s made or how it works. It sounds like it looks different in different lights. There are also references on the Web to “color change sapphire”, “color change alexandrite”, and “color change corundum”.
http://www.geolite.com/cubic.htm

Nice brilliance and color in this oval Portuguese brilliant flower cut gemstone fashioned in an 11x9-mm oval. Pinkish lavender in warm light changing to icy blue in fluorescent light. The CZ’s weight is 7.2 ct. Priced at $6/ct.

http://www.secure-catalog.com/alw/rough.html

Rough - Color Change CZ
$0.10
This Cubic Zirconia changes from a peridot type color to a padparashah sapphire hue. Cuts a magnificent stone. Pricing is per carat.

http://www.morioncompany.com/CubicZirconia.htm

Golden-yellow in daylight and in incandescent light, while olive-green in fluorescent light.

http://www.morioncompany.com/reviews.htm

Among the imitations gem materials being offered by Morion was cubic zirconia (CZ) in a wide range of colors, including a color-change type.

Here with me now I have three actual books (!): Joel Arem’s Gems and Jewelry, Cally Hall’s Gemstones, and the Sterling Publishing Company’s Gemstones. Admittedly, none of these is a big fat specialist tome, but none of them mentions any problems with CZ changing color. Actually, they all make a point of mentioning what an excellent imitation diamond it is. Arem calls it, “Lively, hard, and durable.” He wouldn’t say that if it changed color on you.

My guess would be that your dealer was feeding you a line.

[don_willard]

Thanks for the leads. As for the desired color change, as I understand it they put a little neodymium in the batch and that is the same rare earth element that they put in glass that they use to make alexandrium gems, so-called, and more importantly, that is put in glass for something to do with windows? in spaceships. Neodymium is evidently what they put in a collectible kind of glass that has been made for a long time that is pink in some light and blue in others–I mean glass for glasses and ashtrays, etc. I forget what it is called. I saw a beautiful cold blue-lavender gem in a gift shop that the lady said a local gem cutter cut and that it was “synthetic kunzite.” Or else it was a big pink stone, I forget, but the suprising thing was that when I got it home it was the other color, a completely different stone. It only cost about 30bucks and I ran right back to get another one, as it was so sharply and symmetrically cut, and she had him cut another for me.
Well later on I learned more about kunzite and how it is lithium aluminum silicate and I got a little piece of paper from the lady who got it from the cutter and it said the stone had lithium in it and neodymium (it was all printed up) but as I might have known, it was a piece of glass! So now I had two pieces of beautifully cut glass that changed color and I was very happy, realizing that of course it couldn’t be kunzite, which quite expensive, so I was happy, but it just goes to show the difficulty OTHER people have in conceptualizing that gems are made out of elements.
I have several color change cz’s, of two kinds. 1)one kind changes from a violently attractive intense pink to a pale, very unattractive weak straw color. It is the good pink color in fluorescent light and the bad color in every other kind of light, so I hope they never get rid of fluorescent light. 2) the other kind goes from darkish lavender-purple to pink, depending on the light, and both colors are attractive. I will check out the sites you mentioned and consider the other kinds of color change.
(As you probably know, that purple stone they sell as synthetic alexandrite is corundum and it certainly does not look like an alexandrite at all. Several gem books comment on how it doesn’t. I haven’t got the stones here, but as I remember they are just purple with a hint of maybe some reddish color, and they don’t change depending on the light).