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<front>
<journal-meta>
<journal-id journal-id-type="archive">gsminmag</journal-id>
<journal-title>Mineralogical Magazine</journal-title>
<abbrev-journal-title abbrev-type="full">Mineralogical Magazine</abbrev-journal-title>
<issn pub-type="ppub">0026-461X</issn>
<publisher>
<publisher-name>Mineralogical Society</publisher-name>
</publisher>
</journal-meta>
<article-meta>
<article-id pub-id-type="doi">10.1180/minmag.1971.038.295.04</article-id>
<title-group>
<article-title>Pyrophanite from Chvaletice (Bohemia)</article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname>&#x017D;&#x00E1;k</surname>
<given-names>L.</given-names>
</name>
<aff>Department of mineralogy, geochemistry, and crystallography, Charles University, Prague, Czechoslovakia</aff></contrib></contrib-group>
<pub-date pub-type="ppub">
<month>9</month>
<year>1971</year>
</pub-date>
<volume>38</volume>
<issue>295</issue>
<fpage>312</fpage>
<lpage>316</lpage>
<history>
<date date-type="received">
<day>9</day>
<month>7</month>
<year>1970</year>
</date></history>
<copyright-statement>Copyright &#x00A9; 1971, The Mineralogical Society</copyright-statement>
<copyright-year>1971</copyright-year>
<abstract>
<title>Summary</title>
<p>Pyrophanite was found in quartz-rhodochrosite veins in hornstones of Algonkian pyritemanganese ores. Photometric reflectance falls from R<sub>0</sub> 24 and R<sub>E&#x2032;</sub> 19 at 405 m&#x00B5; to R<sub>0</sub> 18 and R<sub>E&#x2032;</sub> 15% at 656 m&#x00B5; (in air). Vickers microhardness (100 g load) demonstrates directional anisotropy, the average value is 611 kg/mm<sup>2</sup>. Besides the main constituents, subordinate to trace quantities of Mg, Si, Al, Ca, and Cu were recorded by a spectrographic analysis. Unit-cell dimensions are <italic>a</italic> = 5&#x00B7;131 and <italic>c</italic> = 14&#x00B7;27 &#x00C5;. Electron-microprobe analysis gave MnO 43&#x00B7;3, FeO 3&#x00B7;8, MgO 0&#x00B7;05, TiO<sub>2</sub> 52&#x00B7;9, SiO<sub>2</sub> 0&#x00B7;1, total 100&#x00B7;15%. The origin of the Chvaletice pyrophanite was most probably connected with a hydrothermal metamorphism of an Alpine-paragenesis type. The source of elements was older sedimentary, basic volcanic, and metamorphic mineral assemblages.</p></abstract>
</article-meta>
</front>
</article>
