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. Author manuscript; available in PMC: 2018 Dec 10.
Published in final edited form as: Am Mineral. 2014 Jan;99(1):8–15. doi: 10.2138/am.2014.4567

Table 2.

Chemical compositions of erionite and offretite from the Killdeer Mountains

Sample no./ 080603 080603 080603 080603 080603 080603 080603 080604 080604 080604 080603
Grain no. −08/1 −08/2 −08/3 −07/1 −07/2 −07/3 −07/4 −09/3 −08/1 −07/2 −01/1
SiO2 44.86 53.54 43.49 61.82 48.06 54.70 48.72 64.87 67.52 62.45 58.89
Al2O3 12.03 13.90 12.03 15.74 12.03 14.31 12.97 16.36 17.27 15.14 12.90
Fe2O3 1.99 0.28 0.05 0.66 0.17 6.53 0.31 0.12 0.32 0.57 0.08
MgO 1.78 1.04 0.74 1.62 1.35 4.73 1.08 0.37 0.77 0.69 1.29
CaO 2.77 3.85 2.85 3.59 2.63 1.68 3.66 6.00 5.95 4.57 3.14
Na2O 0.16 0.22 0.23 0.16 0.09 0.14 0.17 0.03 0.03 0.05 0.11
K2O 2.41 3.22 3.65 3.02 2.13 2.51 2.71 2.35 2.33 3.20 2.62
H2O n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a.
Si 26.79 27.54 26.60 27.73 27.94 25.80 27.35 27.92 27.78 28.05 28.70
Al 8.47 8.43 9.37 8.32 8.23 7.96 8.61 8.30 8.38 8.01 7.39
Fe3+ 0.90 0.11 0.03 0.22 0.07 2.32 0.13 0.04 0.10 0.19 0.03
Mg 1.58 0.80 0.73 1.08 1.17 3.33 0.90 0.24 0.47 0.46 0.92
Ca 1.78 2.13 2.14 1.72 1.64 0.85 2.21 2.77 2.62 2.20 1.65
Na 0.18 0.22 0.35 0.14 0.11 0.13 0.18 0.02 0.03 0.04 0.11
K 1.84 2.12 3.21 1.73 1.58 1.51 1.94 1.29 1.22 1.84 1.69
Number of points 1 3 2 2 2 1 3 1 1 1 3
Alth 8.73 8.19 9.30 7.48 7.29 9.99 8.35 7.33 7.44 7.20 6.94
E% 7.19 4.25 1.06 14.03 13.89 2.89 4.64 13.82 13.95 13.95 6.91
Si+Al 35.26 35.97 35.97 36.04 36.17 33.76 35.97 36.22 36.15 36.06 36.08
Mg/(Ca+Na) 0.81 0.34 0.31 0.58 0.68 3.40 0.38 0.09 0.18 0.21 0.55
080603 080602 080602 080604 080604
−01/2 −03/1 −03/2 −01/1 −01/3
48.20 61.46 59.53 45.10 64.51
10.98 14.93 14.33 14.44 16.24
0.21 0.24 0.29 0.17 0.03
2.35 2.52 2.61 1.95 1.99
2.73 3.08 3.35 2.92 3.42
0.29 0.02 0.05 0.08 0.05
1.28 1.57 1.30 2.35 2.79
n.a. n.a. n.a. n.a. n.a.
28.08 28.06 27.99 26.29 27.94
7.54 8.04 7.95 9.92 8.29
0.09 0.08 0.10 0.07 0.01
2.04 1.72 1.83 1.70 1.28
1.70 1.51 1.69 1.82 1.59
0.32 0.02 0.05 0.09 0.04
0.95 0.92 0.78 1.75 1.54
1 1 2 1 1
8.76 7.39 7.86 8.88 7.32
–12.91 9.89 2.35 12.46 13.39
35.62 36.10 35.94 36.20 36.23
1.01 1.12 1.06 0.89 0.79

Note: Atomic ratios based on 72 O. The balance error E% = [(Al + Fe3+) − Alth]/Alth × 100 where Alth = Na + K + 2(Ca + Mg + Sr + Ba) (Passaglia 1970).