Daniel E. Appleman
David R. Wones
1963
<p><span>Triclinic KFeSi </span><sub>3</sub><span> O </span><sub>8</sub><span> , iron-microcline, has been synthesized from oxide mixes and by complete conversion of monoclinic KFeSi </span><sub>3</sub><span> O </span><sub>8</sub><span> , iron-sanidine. Iron-microcline is triclinic, </span><i>C</i><span> ī, </span><i>a</i><span> =8·68±0·01 Å, </span><i>b</i><span> =13·10±0·01, </span><i>c</i><span> =7·34±0·01, </span><i>α</i><span> =90° 45′±10′, </span><i>β</i><span> =116° 03′±10′, γ=86°14′±10′. The optical properties (Na light) are: </span><i>α</i><span> =1·585±0·002, </span><i>β</i><span> =1·596±0·002, γ=1·605±0·002, 2 </span><i>V<span> </span><sub>α</sub></i><span> =85° (calc.), X≈ </span><i>b</i><span> , Z ∧ </span><i>c</i><span> =20°±5°. A reversible phase transition between triclinic and monoclinic KFeSi </span><sub>3</sub><span> O </span><sub>8</sub><span> occurs at 704°±6° C at 2000 bars total pressure. Iron-microcline is the low-temperature polymorph; no intermediate polymorphs were observed in either hydrothermal or dry heating experiments.</span></p>
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10.1093/petrology/4.1.131
en
Oxford University Press
Properties of synthetic triclinic KFeSi3O8, iron-microcline, with some observations on the iron-microcline⇌iron-sanidine transition
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