STEININGERITE, [1],
(Ba,K)2(Zr,Ti,Nb)2[Si4O12]O2
You can select three types of scale (Theta, 2-Theta, D(hkl)) and different types of anodes (Cu, Co etc.) for Theta-calculation. Also, by mouse clicking on spectr's peak (or near it - up to 2 pixels) you can receive HKL index(es), intensities and current scale measurement of this peak on bottom.
All scales can be resized (increase/decrease) in horizontal (H+/H-) and vertical (V+/V-) dimensions, vertical scale can be represented in Normal/Logarithmic/Square_Root scales.