• journal_title：The Canadian Mineralogist
• Contributor：Joel D. Grice ; Robert A. Gault ; H. Gary Ansell
• Publisher：Mineralogical Association of Canada
• Date：1984-
• Format：text/html
• Language：en
• journal_abbrev：Can Mineral
• issn：0008-4476
• volume：22
• issue：2
• firstpage：253
• section：Articles

Edingtonite from the Ice River alkaline complex, near Field, British Columbia, is found in nepheline syenite. Its formula (Ba (sub 1.92) K (sub 0.07) ) (sub Epsilon 1.99) Al (sub 4.17) Si (sub 6.23) O (sub 20.66) .7.34H ₂ O, is derived from the chemical analysis: SiO ₂ 36.3, Al ₂ O ₃ 20.6, BaO 28.6, K ₂ O 0.32, H ₂ O 12.8, total 98.62%. Optically it is biaxial negative with alpha 1.535(2), beta 1.542(2) gamma 1.545(2), 2V 62(5) degrees (meas.). Cell refinement yields a 9.583(7), b 9.624(7), c 6.527(6) Aa The density (g/cm ³ ) is 2.73(2) (meas.), 2.75 (calc.). Crystals average 8X2X2 mm with forms {001}, {110}, {111} and {111} (point group 222). Twinning is common on (110) (lamellar) and [001] ₉₀ .(penetration). Edingtonite from the Brunswick No. 12 mine, near Bathurst, New Brunswick, is found as a hydrothermal infilling in a series of metasediments. It has the formula (Ba (sub 2.00) K (sub 0.02) ) (sub Epsilon 2.02) Al (sub 4.23) Si (sub 6.20) O (sub 20.78) .7.22H ₂ O, derived from the chemical analysis: SiO ₂ 35.9, Al ₂ O ₃ 20.8, BaO 29.6, K ₂ O 0.11, H ₂ O 12.5, total 98.91%. Optically it is biaxial negative with alpha 1.538(2), beta 1.549(2) gamma 1.551(2), 2V 56(5) degrees (meas.). Cell refinement yields a 9.551(5), b 9.656(5), c 6.516(6) Aa The density (g/cm ³ ) is 2.78(2) (meas.), 2.76 (calc.). Crystals are as large as 45X10X10 mm with forms {001}, {110}, {101} and {111}, {11} and {211}. Twinning was not observed. Saturated edingtonite has eight H ₂ O molecules. Four H ₂ O molecules may be removed under vacuum, two by heating from 50 to 150 degrees C and two between 150 and 200 degrees C. The separation of the latter four H ₂ O molecules in two steps invalidates the structures as presently known. At 30% of relative humidity and 25 degrees C, 1.00 wt.% H ₂ O is removed from edingtonite.--Journal abstract.