The larger quartz tube was sealed under vacuum. After ramping up to 400 Tomography: The sealed tubes were first examined by x-ray absorption contrast tomography using a Rigaku CTLab GX130 machine at Beckman Institute at University of Illinois to verify presence of crystals in the flux. High resolution absorption contrast tomography (ACT) and LabDCT measurements were carried out using the ZEISS Xradia 620 Versa X-ray microscope (Carl Zeiss X-ray Microscopy, Dublin CA). The objective based dual-magnification setup of the X-ray microscope allowed zooming into the interior region of interest at a higher resolution of 1 µm/voxel without the need for cutting samples to smaller sizes as would be needed on a conventional microCT setup. A full-field of view scan collected at 6 µm/voxel provides a full overview of the tube enabling to pinpoint local regions of interest for high resolution absorption and diffraction contrast tomography. For ACT, 1601 projections were obtained with a 3 s exposure at an X-ray energy of 160 kV at 10 W, using a HE2 high energy filter. The data was reconstructed using the microscope's Powder X-ray diffraction was performed to verify that the crystalline product is single phase.