Joined: Sat Nov 05, 2005 11:51 am Posts: 204 Location: France
Hello, I have a lot of blue spinels. Some of those ones have been sent to several laboratories. I have different answers regarding the name of those stones. Some put Co-spinel / the color comes from Co / contains Co... Many sellers put the name "Cobalt Spinel" without any certificate. So, I am looking if there is a rule about using the name, a scientist rule, what is the rule in the different laboratories. Or is it a "commercial name"?
_________________ Dr Laurent SIKIRDJI http://www.gemfrance.com
Joined: Mon Oct 17, 2005 10:56 am Posts: 6461 Location: The frozen north prairie :-/
While I can't answer for how different labs report on cobalt spinel, I can add this:
Most sellers I've come across use the term "cobalt blue spinel" very loosely. Cobalt blue is defined as "greenish blue", therefore, if a spinel is greenish blue the seller may certainly call it cobalt blue spinel.
However, since blue spinel colored by cobalt is rather rare, and consequently more expensive, I tend to think many sellers play on this when describing their stones.
As with "imperial" garnet, pink emerald, etc., there doesn't seem to be much regulation when it comes to gemstone names .
_________________ IIJA Registered Gemologist GIA Graduate Gemologist
Gemfrance, Im new to this web & I also have some blue spinel but in a pendent, it is considered blue spinel, sometimes cobalt is used as a reference to the ideal color-here is what I have, any comments welcome-m76...
Barbara, I guess if I really wanted to verify the cobalt element I would have the stones tested by a lab. Since my appraisers tell me this is blue spinel & pretty good examples of the material, Im satisfied with the results. The stones r worn by the wife & I, and they do look good depending on the cloths worn with them, according to the boss, wife, who wears the pendents daily. My main concern when showing stones to the forum is that what I call x is x & not a questionable stone, these r one of a kind items & r unique for what they represent. I do appreciate ur comments, thanks-m76...
Joined: Sun Oct 16, 2005 12:22 pm Posts: 21602 Location: San Francisco
m76steve wrote:
Barbara, I guess if I really wanted to verify the cobalt element I would have the stones tested by a lab. Since my appraisers tell me this is blue spinel & pretty good examples of the material, Im satisfied with the results. The stones r worn by the wife & I, and they do look good depending on the cloths worn with them, according to the boss, wife, who wears the pendents daily. My main concern when showing stones to the forum is that what I call x is x & not a questionable stone, these r one of a kind items & r unique for what they represent. I do appreciate ur comments, thanks-m76...
Sorry, I'm not quite getting your point. Blue spinel can be colored by a number of different elements. Cobalt spinel is blue spinel colored by cobalt. That being said,
GIA wrote:
although cobalt blue spinels do owe their vivid color to traces of cobalt, it’s their color that makes them valuable, not the presence of that coloring agent. If your spinel has a rich saturated blue color, it is rare and valuable whether or not it contains traces of cobalt.
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