Blue in sapphires versus spinal

[pregcurious]

There's been a lot of interest in both blue sapphires and cobalt blue spinels. In blue sapphires, top trade color is considered to a medium dark with a slight purple modifier, like silksapphire's lovely stone

Top color in cobalt spinel, however, is very different, as shown in the picture from Pala. It's a highly saturated medium blue. To me it almost looks like it has a slight green modifier. Does it look like that to you? I am really bad at green modifiers (as LD knows).

 

[JewelFreak]

I don't see a green modifier, Preg, but maybe a little purplish on my monitor. At any rate, both those stones make me just die of pure lust. This is one subject where it would be most helpful to put a blue spinel side by side w/a blue sapphire IRL -- you can see the differences that way. Gem shows are about the only place I can think of to do it.

--- Laurie

 

[katharath]

I'm very curious about this subject and have been wondering about the comparison, so thanks for posting about it. Looking forward to maybe seeing more pics and POVs.

 

[ChrisA222]

I don't know if top color Cobalt Spinel has to be medium, I think it just has to be devoid of any grey or green tones. I may be biased

 

[chrono]

The Luc Yen blue spinels are coloured by cobalt and chromium, so their colouration is unique and distinctive. Cobalt spinels from elsewhere have very little Cr+3 to none, hence appear different. My 2 cobalt spinels are dead ringers for fine medium dark, well saturated blue sapphires. It is much harder to find very fine blue spinels than very fine untreated blue sapphires.

 

[OTL]

No, definitely no green modifier to me...that's just blue, that's the beauty about these windex blue spinels, it is so rare to see natural things with that pure blue color.

 

[minousbijoux]

I don't know if top color Cobalt Spinel has to be medium, I think it just has to be devoid of any grey or green tones. I may be biased

+1. That said, again just like with sapphires, there is a bias away from the darker but vivid stones.

 

[minousbijoux]

No, definitely no green modifier to me...that's just blue, that's the beauty about these windex blue spinels, it is so rare to see natural things with that pure blue color.

Sorry, but that is not windex color - at least not what we in the US consider Windex color (OTL, I know you live in Canada and for all I know your version is darker! )

Preg: no green there. Just vivid blue, except where it appears it reflecting back something that is violet.

 

[Justin_Cutter]

I see pure medium blue tone with small flashes of magenta.

~Justin

 

[LD]

No green modifier at all in that one Preg.

 

[pregcurious]

Thanks everyone. See, I'm bad at green modifiers. I don't own any blue stones, for a reason. I can't buy distinguish them worth a darn, and would end up overpaying.

I've seen trade people call the vivid medium blue cobalt spinels (like the one above) "windex", even though it may not be the color of actual Windex. I'm partial to the medium cobalt blue spinels, versus the ones that look like top sapphire, but that is just me.

 

[chrono]

Three different examples of blue spinels, all from different locations. I know the one from Pala was tested for both cobalt and chromium but don't know if it was earned the cobalt name. I think it is likely though. The 84 ct stone did not get the cobalt name from SSEF but I don't know if SSEF prints such terms on their memos. The last one was advertised as a cobalt spinel.