1 10 2 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/7b2be47bf331c3137fab55b54dd00400.jpg 4df92e4c361bdf836240b34aa1def201 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/a9feaa0d7b228322ef58f10eabce759a.jpg 2b6715ada6c2fb263e952153d2c695a1 Physical Object An inanimate, three-dimensional object or substance. Note that digital representations of, or surrogates for, these objects should use Moving Image, Still Image, Text or one of the other types. Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource <h2>Hematite</h2> Description An account of the resource <div class="element"> <h3>Formula</h3> <div class="element-text"> <p>Fe₂O₃</p> </div> </div> <div class="element"> <h3>Structure</h3> <div class="element-text"> <p>Non-silicate</p> </div> </div> <div class="element"> <h3>Crystal System</h3> <div class="element-text"> <p><em>Crystal system:</em><span> </span>trigonal (-)</p> </div> </div> <div class="element"> <h3>Physical Properties</h3> <div class="element-text"> <p class="NoSpacing"><em><span>Colour in hand specimen: </span></em><span>black, steel-grey and bright to dull red</span><span> </span><br class="NoSpacing" /><em><span>Streak:</span></em><span> cherry-red</span><span> </span><br class="NoSpacing" /><em><span>Cleavage:</span></em><span> none</span><span> </span><br class="NoSpacing" /><em><span>Hardness:</span></em><span> 5-6</span></p> </div> </div> <div class="element"> <h3>Optical Properties</h3> <div class="element-text"> <p class="NoSpacing"><em><span>Colour in plane polarised light:</span></em><span> opaque; blood-red in very thin splinter</span><span> </span><br class="NoSpacing" /><em><span>Pleochroism:</span></em><span> none</span><span> </span><br class="NoSpacing" /><em><span>Relief:</span></em><span> high</span></p> </div> </div> <div class="element"> <h3>Mineral Specimens</h3> <div class="element-text"> <p class="NoSpacing"><strong><span>M500 Hematite</span></strong><span> </span><br class="NoSpacing" /><strong>Cumberland</strong><strong></strong><span> </span><br class="NoSpacing" />A concretionary mass showing concentric and radial structure<span> </span><br class="NoSpacing" />Silvery black with a red streak<span> </span><br class="NoSpacing" />Oxidised to dark brown-red in places<span> </span><br />Metallic lustre</p> </div> </div> <div class="element"> <h3>Rock Specimens</h3> <div class="element-text"> <p><a href="/p1acollections/exhibits/show/sedimentary-rocks/l310">L310 Breccia</a><span> </span><br /><a href="/p1acollections/exhibits/show/sedimentary-rocks/l311">L311 Conglomerate</a><span> </span><br /><a href="/p1acollections/exhibits/show/sedimentary-rocks/l324">L324 Sandstone, feldspathic arenite</a><span> </span><br /><a href="/p1acollections/exhibits/show/sedimentary-rocks/l326">L326 Sandstone, ferruginous arenite</a><span> </span><br /><a href="/p1acollections/exhibits/show/sedimentary-rocks/l340">L340 Mudstone</a><span> </span><br /><a href="/p1acollections/exhibits/show/sedimentary-rocks/l354">L354 Limestone, shelly</a><br /><a href="/p1acollections/exhibits/show/metamorphic-rocks/l500">L500 Slate</a></p> </div> </div> <div class="element"> <h3>Mineral Name</h3> <div class="element-text">hematite<br />iron oxide<br />opaques</div> </div> oxidation sedimentary https://wserv3.esc.cam.ac.uk/p1acollections/files/original/3fe81164e89cb8ce7ea324619c4a6800.jpg 4fba4b4108c529ccb7c8638941813e9f https://wserv3.esc.cam.ac.uk/p1acollections/files/original/0f351e1be30ed9218d69f6e7be19c538.jpg 375d8c343a9559d5141db30e65426acc https://wserv3.esc.cam.ac.uk/p1acollections/files/original/4a7d0ec7c3d779cc3bb42f7856e405ef.jpg 7efb2834c8830784edcdb8e129cd4848 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/24f4a832b846ebe79e388cd619f863af.jpg 2c40579ff6e440ee59364245fffabef6 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/a510299fa5a7c375958cbe1f972da092.jpg 89e9195c406cb49ad3d667bce0a238f9 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/28f8f145e2f3fbe758a59b9a674fec61.jpg e63f4971fc2cbfa3a255b7dd89f6a6d7 Physical Object An inanimate, three-dimensional object or substance. Note that digital representations of, or surrogates for, these objects should use Moving Image, Still Image, Text or one of the other types. Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource <h2><strong>L340<br /></strong></h2> <h2>Mudstone</h2> Subject The topic of the resource <h3>Age</h3> <div class="element-text">Cambrian<br /><h3>Location</h3> <div class="element-text">Solva, South Wales</div> </div> Description An account of the resource <div class="element"> <h3>Hand Specimen</h3> <div class="element-text">Superficially specimens “a” and “b” look very different due to their colours. L340a is pale grey, while L340b is dark purple-red. The colour of L340b indicates that it is ferruginous, containing significant quantities of iron oxide.<br /><br />These are mudstones, made up of clay and/or silt sized grains.<span> </span><br />Contain some glinting mica flakes.<span> </span><br />Do not react with acid, so do not contain significant carbonate.</div> </div> <div class="element"> <h3>Thin-section</h3> <div class="element-text"> <p>L340a<span> </span><br />- Homogeneous texture apart from one hairline quartz vein. Mainly mud sized grains too small to be distinguished, but probably clay minerals. Some silt sized grains of quartz, plagioclase and white mica. Patches of minor red-brown<span> </span><span>iron staining</span>.</p> <p>L340b<span> </span><br />- Hold up to light to see discontinuous, wavy laminations. Mud sized grains of quartz, feldspar, white mica and opaque minerals. Red<span> </span><span>iron-staining</span>.</p> </div> </div> <div class="element"> <h3>Rock History</h3> <div class="element-text">The dark purple-red of L340b indicates an oxidising environment during diagenesis, while the grey colour of L340a indicates a reducing environment.<br /><br />Non-marine environments are more likely to be oxidising than marine environments where organic matter tends to promote a reducing environment during diagenesis. Reducing environments are associated with grey, black or greenish rocks.</div> </div> <div class="element"> <h3>Advanced Notes</h3> <div class="element-text"> <p><span>Iron staining</span><span> </span><br />Hematite (Fe2O3) → red (blood-red, cherry-red, brown-red) iron-staining<span> </span><br />Limonite (FeO(OH)•nH2O) → yellow or brown iron-staining</p> <p>The red / red-brown colours of these rocks is probably produced by hematite.</p> </div> </div> <div class="element"></div> <div class="element"></div> <div class="element"> <h3>Rock Name</h3> <div class="element-text">mudstone</div> </div> oxidation reduction