Line color pattern in sapphires

[DotDot]

Hi PSers,

Recently I saw a heated sapphire at a local store. It looks nice from top down. However when it's turned up side down, I noticed a line pattern. I was able to observe it without loupe. It looks like lots threads that are slightly darker blue than background running through. I am hoping to find out if this is considered zoning, inclusion, heating pattern, indication of other treatments? It was marketed as heated natural sapphire with no certs.

Thanks for your help!! Sorry no pics.

 

[LD]

It sounds like zoning. Did it look like the photo below?

 

[LoversKites]

Yes most probably colour zoning. From what I have seen, as long as the zoning doesn't appear face-up, it doesn't affect the price of the stone.

 

[ephsea]

Unless you're planning to mount the stone upside down, it shouldn't be a problem. This is common with heat-teated sapphires.

 

[FrekeChild]

Unless you're planning to mount the stone upside down, it shouldn't be a problem. This is common with heat-teated sapphires.

No it isn't. It has to do with how corundum crystal grows. It has nothing to do with heating.

Color zoning—areas of different colors in a stone—is a common sapphire characteristic. Blue sapphire often has angular zones of blue and lighter blue. To accommodate color zoning in some sapphires, cutters orient the concentrated color in a location that offers the best visible color in the cut stone.

http://www.gia.edu/sapphire-quality-factor

 

[treasurehunter]

When they heat those rutile needles they form those blue hazy lines which are a good indication of heat treatment as the rutile dissolves to release the blue colour.

 

[ephsea]

Well I still have a lot to learn, but it was my understanding that sapphires which have rutile present are candidates to be improved be "natural" heat, as the heat dissolves the titanium in the rutile, which is what makes a sapphire blue? If they were growth lines (like in the example pic above), then wouldn't they be less likely to be blue? We don't have a picture of the stone in question, so it's hard to say? Here's a blue galaxy giving one of my heated montana's it's color. If I had a macro lens, you could see that it's actually a hazy swirl.

 

[athenaworth]

The lines in the photo above are just growth lines. They can happen in heated or unheated stones and most cutters orient the stone so that the lines don't show when it's face up, unless the color zoning creates some sort of interesting look. The breaking up of rutile needles during the heating process can change the tone or saturation of the stone, bit doesn't cause the angular growth lines. Note: if the lines are curved instead of straight, that is an indication that the stone may be synthetic.

 

[FrekeChild]

However when it's turned up side down, I noticed a line pattern. I was able to observe it without loupe. It looks like lots threads that are slightly darker blue than background running through.

If it's seen without a loupe, and it's lines of darker blue on lighter blue/colorless/yellow/whatever, it's color zoning.

ETA: pic

 

[ephsea]

Thanks for the good pic - I see. Very different from the hazy lines I see in heated stones. I think it's really cool, I can see wearing something like that if the growth pattern was right...

 

[kenny]

Is that not called graining?

Here's a pic of graining in my Fancy Deep Purplish-Pink diamond.
These lines are not visible in the face up view.

 

[minousbijoux]

No, it is not. In corundum its called color zoning. I mean, why have one set of terms when two will confuse people more?

 

[FrekeChild]

Thanks for the good pic - I see. Very different from the hazy lines I see in heated stones. I think it's really cool, I can see wearing something like that if the growth pattern was right...

Parti sapphires! Couple parti sapphires I found pics of, and one from Jean Noel Soni. Most of the ones I found are blue/yellow, but others exist out there.

 

[pregcurious]

Kenny, your photography never ceases to amaze me.

 

[DotDot]

Thanks for all the discussion. What I saw is what showed in the first picture, color zoning then. Thanks.

 

[kenny]

Thanks Pregcurious.

 

[Indylady]

Kenny, your photography never ceases to amaze me.

+1.