Prepared α-AL2O3 particles of sizes ≤ 20 μm for the certification and dissemination of CRM materials to calibrate powder X-ray diffraction equipment. The crystallinity of the material was improved by annealing at 1400 0C for 11 hrs. The XRD pattern was recorded with a step size of 0.0050/3 sec and specimen spinning speed of 30 rpm. The entire powder pattern shows that the material is well crystalline with FWHM of 0.0450 for the 113 diffraction peak. The diffraction pattern matches well with PDF file 10-0173 of ICDD. The material crystallizes in rhombohedral and the cell parameter calculated as a = 4.7736 ± 0.0034 A0, c = 12.9930 ± 0.0022 A0, c/a = 2.72185, Z = 6, Dx = 3.989 A0. The repeatability of the powder data result was verified by replicate measurements (10 numbers) performed over a period of time. Like this, twelve different laboratories including few foreign labs participated in the certification procedure. The material was released on 5th November 2007 and is now available for its use.