Why does this sapphire look like this?

[pregcurious]

I saw this sapphire when browsing for other posters, and noticed that it has what looks like diagonal lines across the face. Is this color zoning?

Also, I do not see a window, but the depth seems borderline. It makes for a spready stone.

Sapphire Round "Portuguese" Style Cut
Weight: 1.15 cts
Measurements: 6.5mm, depth 3.8mm
Clarity: VVS
Origin: Sri Lanka
Enhancements: Heat only

 

[minousbijoux]

Yep, my guess from that tiny picture is zoning - looks pretty classic. I don't know the price, but it should have a lower price than a similar stone without zoning.

 

[pregcurious]

Thanks, Minou.

 

[chrono]

I cannot tell for sure if it is zoning or silk. More likely to be zoning though, considering the pattern, size and location.