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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.1972.038.297.01</article-id>
<title-group>
<article-title>Zapatalite, a New Mineral from Sonora, Mexico</article-title>
</title-group>
<contrib-group>
<contrib contrib-type="author">
<name>
<surname>Williams</surname>
<given-names>Sidney A.</given-names>
</name>
<aff>British Museum (Natural History), London, S.W. 7, England<xref ref-type="author-notes" rid="FN1">1</xref></aff></contrib></contrib-group>
<author-notes>
<fn fn-type="present-address" id="FN1"><label>1</label><p>Permanent address: Phelps Dodge Corporation, Douglas, Arizona, 85607, U.S.A.</p></fn></author-notes>
<pub-date pub-type="ppub">
<month>3</month>
<year>1972</year>
</pub-date>
<volume>38</volume>
<issue>297</issue>
<fpage>541</fpage>
<lpage>544</lpage>
<history>
<date date-type="received">
<day>20</day>
<month>4</month>
<year>1971</year>
</date></history>
<copyright-statement>Copyright &#x00A9; 1972, The Mineralogical Society</copyright-statement>
<copyright-year>1972</copyright-year>
<abstract>
<title>Summary</title>
<p>Zapatalite, Cu<sub>3</sub>Al<sub>4</sub>(PO<sub>4</sub>)<sub>3</sub>(OH)<sub>9</sub>&#x00B7;4H<sub>2</sub>O, was first found at a small prospect north-west of Cerro Morita, 27 kilometers south-west of Agua Prieta, Sonora. It occurs in silicified and brecciated limestone with libethenite, chenevixite, beaverite, alunite, and pseudomalachite.</p>
<p>Zapatalite is pale (faience) blue with pale blue streak; H = 1<inline-formula><mml:math><mml:mfrac><mml:mn>1</mml:mn><mml:mn>2</mml:mn></mml:mfrac></mml:math></inline-formula>, G = 3&#x00B7;016&#x00B1;0&#x00B7;026. It is soluble in cold dilute acids and decomposed by 20% KOH. Duplicate analyses on samples of about 9 and 15 mg gave CuO 27&#x00B7;92, 25&#x00B7;77%; Al<sub>2</sub>O<sub>3</sub> 20&#x00B7;16, 20&#x00B7;26%; P<sub>2</sub>O<sub>5</sub> 20&#x00B7;69, 22&#x00B7;51%; H<sub>2</sub>O 15&#x00B7;46, 15&#x00B7;79%; insol. (baryte and quartz), 15&#x00B7;46, 15&#x00B7;79%. This leads to the formula Cu<sub>3</sub>Al<sub>4</sub>(PO<sub>4</sub>)<sub>3</sub>(OH)<sub>9</sub>&#x00B7;4H<sub>2</sub>O.</p>
<p>The cell can be indexed as tetragonal with <italic>a</italic> 15&#x00B7;22&#x00C5;, <italic>c</italic> 11&#x00B7;52&#x00C5;, and a volume of 2669&#x00C5;<sup>3</sup>. If <italic>Z</italic> = 6, empirical cell contents are Cu<sub>19&#x00B7;4</sub>Al<sub>22&#x00B7;8</sub>(PO<sub>4</sub>)<sub>17&#x00B7;6</sub>(OH)<sub>55&#x00B7;4</sub>22&#x00B7;2H<sub>2</sub>O, and the calculated G = 3&#x00B7;017. Strongest lines of the powder pattern are 7&#x00B7;62 (10), 11&#x00B7;60 (10), 5&#x00B7;75 (7), 6&#x00B7;82 (7), 3&#x00B7;04 (5), 2&#x00B7;53 (5), 2&#x00B7;95 (4), and 2&#x00B7;88 (4).</p>
<p>Pale green in thin section with feeble dichroism in green, with <italic>&#x03B5;</italic> &#x003E; <italic>&#x03C9;</italic>. The good basal cleavage is a length slow direction. Indices for Na-<italic>D</italic> are <italic>&#x03B5;</italic> = 1&#x00B7;635, <italic>&#x03C9;</italic> = 1&#x00B7;646. Usually uniaxial (&#x2014;), but may be biaxial (&#x2014;) with variable 2 V.</p>
<p>Named for Emiliano Zapata (1879&#x2013;1919), a popular hero of the Mexican revolution. Type specimens to be left with British Museum (Natural History) and the University of Arizona.</p></abstract>
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