{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/64605"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/64605","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"The crystal chemistry of staurolite","abstract":"Microprobe analyses of 20 staurolites from many localities indicate that the range of composition of natural ferroan specimens is Fe2.95-3.44 Al17.07-17.60Mg0.38-1.13Ti0.09-0.14Zn0-0.17Mn0-0.09Cr0-0.02V≤.01.Co≤.004 Si7.64-7.91O44 OH~4. Our observations, together with chemical analyses and other experimental evidence from the literature, are sufficient to conclude that the staurolite unit cell contains ~4 H⁺ in agreement with the structural formula of Smith (1968): (7 octahedral sites, principally Al)~18 (1 tetrahedral site, principally Fe)≤₄ (1 tetrahedral site, principally Si)₈O₄₈H≤₄ Assuming that Si and a small amount of Al fill the SiIV site, we have used the method of principal component analysis to deduce that the primary substitution in the A1VI sites is Al ⇄ (Fe+Mg+Ti) and that in the FeIV sites is Fe ⇄ (Zn+Al). Secondary substituents in the AIIVsites are M and Zn, and it is likely that small amounts of and Ti are present in the FeIV site. The generally accepted view that Mg is the primary substituent for Fe in the FeIV site is not supported Lattice parameters determined by powder methods on 15 analyzed staurolites show the following ranges: a= 7.865 - 7.879Å; b = 16.600 - 16,633Å; c = 5.656 - 5.664Å; β = 90.0°. There are positive correlations of b and c with Fe content, while a is nearly independent of composition. These relationships are explained on the basis of the crystal structure and site occupancies. Natural specimens have uniformly shorter a cell edges {by ~0.015Å) than synthetic Fe-Mg staurolites. Improved curves showing the relationship of 2V and refractive indices to Fe-content have been established.","abstract_html":"Microprobe analyses of 20 staurolites from many localities indicate that the range of composition of natural ferroan specimens is Fe<sub>2.95-3.44</sub> Al<sub>17.07-17.60</sub>Mg<sub>0.38-1.13</sub>Ti<sub>0.09-0.14</sub>Zn<sub>0-0.17</sub>Mn<sub>0-0.09</sub>Cr<sub>0-0.02</sub>V<sub>≤.01</sub>.Co<sub>≤.004</sub> Si<sub>7.64-7.91</sub>O<sub>44</sub> OH<sub>~4</sub>. Our observations, together with chemical analyses and other experimental evidence from the literature, are sufficient to conclude that the staurolite unit cell contains ~4 H⁺ in agreement with the structural formula of Smith (1968): (7 octahedral sites, principally Al)<sub>~18</sub> (1 tetrahedral site, principally Fe)<sub>≤</sub>₄ (1 tetrahedral site, principally Si)₈O₄₈H<sub>≤</sub>₄ Assuming that Si and a small amount of Al fill the Si<sup>IV</sup> site, we have used the method of principal component analysis to deduce that the primary substitution in the A1<sup>VI</sup> sites is Al ⇄ (Fe+Mg+Ti) and that in the Fe<sup>IV</sup> sites is Fe ⇄ (Zn+Al). Secondary substituents in the AI<sup>IV</sup>sites are M and Zn, and it is likely that small amounts of and Ti are present in the Fe<sup>IV</sup> site. The generally accepted view that Mg is the primary substituent for Fe in the Fe<sup>IV</sup> site is not supported Lattice parameters determined by powder methods on 15 analyzed staurolites show the following ranges: a= 7.865 - 7.879Å; b = 16.600 - 16,633Å; c = 5.656 - 5.664Å; β = 90.0°. There are positive correlations of b and c with Fe content, while a is nearly independent of composition. These relationships are explained on the basis of the crystal structure and site occupancies. Natural specimens have uniformly shorter a cell edges {by ~0.015Å) than synthetic Fe-Mg staurolites. Improved curves showing the relationship of 2V and refractive indices to Fe-content have been established.","abstract_has_math":false,"creators":["Griffen, Dana T."],"institution":"Virginia Polytechnic Institute and State University","degree_name":"Master of Science","degree_level":"masters","degree_discipline":"Geological Sciences","degree_department":"Geological Sciences","school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":1972,"date_issued":"1972","date_published":"1972","updated_at":"2026-07-22T22:19:47Z","subjects":[],"languages":["en"],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/10919/64605","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.department","label":"Department","values":["Geological Sciences"]},{"key":"dc:creator","label":"Author","values":["Griffen, Dana T."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2016-02-01T14:45:02Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2016-02-01T14:45:02Z"]},{"key":"dc:date.issued","label":"Date","values":["1972"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Polytechnic Institute and State University"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.dcmitype","label":"Dc Type Dcmitype","values":["Text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Geological Sciences"]},{"key":"thesis:degree_level","label":"Degree Level","values":["masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Virginia Polytechnic Institute and State University"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["In Copyright"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://rightsstatements.org/vocab/InC/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/64605"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Microprobe analyses of 20 staurolites from many localities indicate that the range of composition of natural ferroan specimens is Fe2.95-3.44 Al17.07-17.60Mg0.38-1.13Ti0.09-0.14Zn0-0.17Mn0-0.09Cr0-0.02V≤.01.Co≤.004 Si7.64-7.91O44 OH~4. Our observations, together with chemical analyses and other experimental evidence from the literature, are sufficient to conclude that the staurolite unit cell contains ~4 H⁺ in agreement with the structural formula of Smith (1968): (7 octahedral sites, principally Al)~18 (1 tetrahedral site, principally Fe)≤₄ (1 tetrahedral site, principally Si)₈O₄₈H≤₄ Assuming that Si and a small amount of Al fill the SiIV site, we have used the method of principal component analysis to deduce that the primary substitution in the A1VI sites is Al ⇄ (Fe+Mg+Ti) and that in the FeIV sites is Fe ⇄ (Zn+Al). Secondary substituents in the AIIVsites are M and Zn, and it is likely that small amounts of and Ti are present in the FeIV site. The generally accepted view that Mg is the primary substituent for Fe in the FeIV site is not supported Lattice parameters determined by powder methods on 15 analyzed staurolites show the following ranges: a= 7.865 - 7.879Å; b = 16.600 - 16,633Å; c = 5.656 - 5.664Å; β = 90.0°. There are positive correlations of b and c with Fe content, while a is nearly independent of composition. These relationships are explained on the basis of the crystal structure and site occupancies. Natural specimens have uniformly shorter a cell edges {by ~0.015Å) than synthetic Fe-Mg staurolites. Improved curves showing the relationship of 2V and refractive indices to Fe-content have been established."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science"]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["The crystal chemistry of staurolite"]}]}],"canonical_facts":{"dc:contributor.department":["Geological Sciences"],"dc:creator":["Griffen, Dana T."],"dc:date.accessioned":["2016-02-01T14:45:02Z"],"dc:date.available":["2016-02-01T14:45:02Z"],"dc:date.issued":["1972"],"dc:description.abstract":["Microprobe analyses of 20 staurolites from many localities indicate that the range of composition of natural ferroan specimens is Fe2.95-3.44 Al17.07-17.60Mg0.38-1.13Ti0.09-0.14Zn0-0.17Mn0-0.09Cr0-0.02V≤.01.Co≤.004 Si7.64-7.91O44 OH~4. Our observations, together with chemical analyses and other experimental evidence from the literature, are sufficient to conclude that the staurolite unit cell contains ~4 H⁺ in agreement with the structural formula of Smith (1968): (7 octahedral sites, principally Al)~18 (1 tetrahedral site, principally Fe)≤₄ (1 tetrahedral site, principally Si)₈O₄₈H≤₄ Assuming that Si and a small amount of Al fill the SiIV site, we have used the method of principal component analysis to deduce that the primary substitution in the A1VI sites is Al ⇄ (Fe+Mg+Ti) and that in the FeIV sites is Fe ⇄ (Zn+Al). Secondary substituents in the AIIVsites are M and Zn, and it is likely that small amounts of and Ti are present in the FeIV site. The generally accepted view that Mg is the primary substituent for Fe in the FeIV site is not supported Lattice parameters determined by powder methods on 15 analyzed staurolites show the following ranges: a= 7.865 - 7.879Å; b = 16.600 - 16,633Å; c = 5.656 - 5.664Å; β = 90.0°. There are positive correlations of b and c with Fe content, while a is nearly independent of composition. These relationships are explained on the basis of the crystal structure and site occupancies. Natural specimens have uniformly shorter a cell edges {by ~0.015Å) than synthetic Fe-Mg staurolites. Improved curves showing the relationship of 2V and refractive indices to Fe-content have been established."],"dc:description.degree":["Master of Science"],"dc:format.mimetype":["application/pdf"],"dc:identifier.uri":["http://hdl.handle.net/10919/64605"],"dc:language.iso":["en"],"dc:publisher":["Virginia Polytechnic Institute and State University"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:title":["The crystal chemistry of staurolite"],"dc:type":["Thesis"],"dc:type.dcmitype":["Text"],"thesis:degree_discipline":["Geological Sciences"],"thesis:degree_level":["masters"],"thesis:degree_name":["Master of Science"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:19:47Z"}