A new type of X-ray powder diffractometric specimen holder made of quartz crystal plate parallel to (11.21) is recommended in this paper. A comparison of this new specimen holder with the holders available indicates that for this holder, instead of having a wide diffraction halo which is shown in the diffractometric curve of glass slide or diffraction peaks produced by specimen holder themselves which are present for unglazed ceramic tile or silver membranaceous filter, there is only an extremely low and smooth background in its diffractometric curve. It is andoubted that this new single-crystal non-diffracted specimen holder invented by the author would be helpful to the improvement of accuracy on determining diffraction patterns in the X-ray diffractometric powder technique.