FERRO-PAPIKEITE, [1], structure type - anthophyllite, DN,
Na(Fe2+,Mg)2[Fe2+3Al2][Si5Al3O22](OH)2
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.