Yellow Sapphire help

Just wondering if someone can tell me what this is I’m seeing… all tests say yellow sapphire, I’m just wondering what the picture is showing where the yellow ‘clouds’ are? From top view the stone is a beautiful yellow and from underneath I can see just a cloud of yellow and almost colourless around it. I want to say this is glass filled? Or is it just strong localised colour zoning?

Those clouds (and clear rims) are possible indicators of a high heat. You may have a yellow sapphire whose color has been assisted with beryllium diffusion. These days a very high % of heated yellow sapphires on the market (~80%) are Be diffused to get a better yellow.

Bear, Pres.

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Ah thank you for your help! That has confirmed what I thought after a bit more investigation it doesn’t seem like glass filling.

I always test surface diffusion by plopping the stone an immersion cell under indirect lighting, (water works if you don’t have any fluids with a higher RI like cinnamon oil). Look at it under 10x and note the color differences from facet to facet. If the color is darker along any of the facet boundaries you know for sure it is color enhanced with diffusion. Natural color zoning does not follow facets.

Hi not sure but I initially thought it could be silk? what they call minute rutile crystals in sapphire can create a hazy effect… if it was glass filled you would invariably see some bubbles in the glass and would not think that the sapphire would be that clean/clear.