Natural Pearls/which type of xray? Bonhams asked for it

[lemanmls]

Now, there is a problem. There is a comment has been made by an Italian jewellery maker friend of mine, that the black marks on the pearl x-ray are most probably not grafts but fissures ( ?) which can be mistaken with cavities on a beadless cultured pearl.Your opinions are highly appreciated. So confused I am
Do you think at this point is it better that I bring them to test personally when I am back. Anyway, I will be using the mentioned two labs in my own research for other gemstones & semi-precious stones. The worst part is that I am studying all gem stones at the moment and will have access to the main labs in Istanbul BUT I won't have anyone for interpretation of the results.
Do you think a tomography or micro spectroscopy ( I will give up 1-2 pearls) is a more valuable tool to identify??

 

[Lagoon Island Pearls]

Now, there is a problem. There is a comment has been made by an Italian jewellery maker friend of mine, that the black marks on the pearl x-ray are most probably not grafts but fissures ( ?)

There is no problem. Fissures are cracks. The contrasts in the views are not cracks.

A cursory inspection yielded a 9:1 score of cultural origin and subsequent x-radiographic images clearly confirm the identification.