The crystal structure of strontian potassicrichterite (Mg4.871Fe0.1263+ Mn0.052)Σ5.049(Na1.425Ca0.348Sr0.297)σ2.07K0.873Si8.048O22(OH)2.15 – an unusual amphibole containing up to 3.7 wt.% SrO from the Murun alkaline massif, Eastern Siberia has been refined from X-ray powder diffraction data in monoclinic space group C2/m, with a = 10.0325(1) Å, b = 17.977(1) Å, c = 5.2698(1) Å, and β = 104.70(1)°. According to Mössbauer spectroscopy, nearly all iron occurs as Fe3+ in octahedral coordination. Rietveld refinement shows the Fe3+ to be ordered onto the M(2) site. Sr is completely ordered onto M(4).