Evidently, the diffusion coefficient is sensitive to impurities or structural issues within the crystal, but that remains for being quantified. For our rough estimates of the time at temperature necessary to remove the hydrogen from our samples, the hydrogen diffusion coefficient chosen is the fact offered by Belonoshko et al. https://directmysocial.com/story2646203/the-best-side-of-sri-lankan-yellow-sapphire