It does look part pearl and part marble, when you say pure pearl do you mean both parents pearl or do you know more of the bloodline....I only ask as wonder if somewhere in the genetic make up is a Motoro of some sort? I do think the pearl and marble might be quite close and wonder if the marble Motoro came about from pearl and Motoro breeding in the wild perhaps? This could all be complete BS though so please do not think it is a slight on a beautiful Pearl and I know you are not one to "ham up" the names and call it a pure if you did not have reason to back that up.
I think it looks quite like the second born of the ones I bred?