Potassic-arfvedsonite Pekov I V, Chukanov N V, Lebedeva Y S, Pushcharovsky D Y, Ferraris G, Gula A, Zadov A E, Novakova A A, Petersen O V Neues Jahrbuch fur Mineralogie, Monatshefte 2004 (2004) 555-574 Potassicarfvedsonite, KNa2Fe2+4Fe3+Si8O22(OH)2,a K-dominant amphibole of the arfvedsonite series from agpaitic pegmatites - Mineral data, structure refinement and disorder in the A site Locality: Ilimaussaq, Greenland _database_code_amcsd 0014932 10.002 18.054 5.319 90 103.90 90 C2/m atom x y z occ Uiso KA'm .013 .5 .039 .342 .038 NaA"m .067 .5 .121 .054 .021 NaA2 0 .472 0 .054 .034 Fe2+M1 0 .09102 .5 .70 .00873 Fe3+M1 0 .09102 .5 .20 .00873 MnM1 0 .09102 .5 .10 .00873 Fe2+M2 0 .18388 0 .58 .00721 Fe3+M2 0 .18388 0 .39 .00721 Ti4+M2 0 .18388 0 .03 .00721 Fe2+M3 0 0 0 .63 .00782 LiM3 0 0 0 .28 .00782 Fe3+M3 0 0 0 .09 .00782 NaM4 0 .27795 .5 .0165 Si1 .27470 .08610 .29088 .00669 Si2 .28655 .17085 .79998 .00683 O1 .10992 .09152 .2078 .0096 O2 .12016 .17285 .7336 .0102 O3 .1084 0 .7081 .8 .0124 F3 .1084 0 .7081 .2 .0124 O4 .3643 .24753 .7991 .0130 O5 .34497 .12684 .0802 .0107 O6 .3374 .11819 .5814 .0115 O7 .3271 0 .2968 .0131 H .223 0 .771 .8 .07