Does any lab certify amethyst as untreated?

[Garry H (Cut Nut)]

We have a client request.
I never thought it possible to determine if the purple is natural color.
Only that the stone is uncoated and not synthetic????

 

[Bron357]

I think the problem is that heat treatment, which is apparently pretty common, isn’t easy to detect lab examination. Unlike corundum which has inclusions that are affected by heat treatment thus indicating heat treatment, Amethyst has no internal features that can be viewed or examined for evidence of treatment.

 

[Gloria27]

I think the problem is that heat treatment, which is apparently pretty common, isn’t easy to detect lab examination. Unlike corundum which has inclusions that are affected by heat treatment thus indicating heat treatment, Amethyst has no internal features that can be viewed or examined for evidence of treatment.

Wait, what? Doesn't amethyst change into citrine or prosiolite if heated because of the iron in the stone?

 

[Garry H (Cut Nut)]

Wait, what? Doesn't amethyst change into citrine or prosiolite if heated because of the iron in the stone?

Yes Bron and Gloria.
As I understand the very dark amethyst may be lightened and made brighter with a little heat, but a lot more turns it into citrine.
But it's nearly 50 years since I studied Gemology.
And my sales team want a stone for a client with a certificate. Like Bron I doubt anyblab can tell. And the cert would cost more than the stone even if it were feasible!
Am I missing something?