1 10 2 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/ac4a4b68b6b2ad4fef27b63699c1a3bf.jpg 7f450bfca482d0fe4649c3f6f70d4afa 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>Clinopyroxene (augite)</h2> Description An account of the resource <div class="element"> <h3>Formula</h3> <div class="element-text">(Ca,Mg,Fe²⁺,Fe³⁺,Ti,Al)₂[(Si,Al)₂O₆]</div> </div> <div class="element"> <h3>Structure</h3> <div class="element-text"> <p>Chain silicate</p> </div> </div> <div class="element"> <h3>Crystal System</h3> <div class="element-text"> <p><em>Crystal</em><em><span> </span>system:</em><span> </span>monoclinic (+)</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</span><span> </span><br class="NoSpacing" /><em><span>Cleavage:</span></em><span> two at 90°</span><span> </span><br class="NoSpacing" /><em><span>Hardness:</span></em><span> 5.5-6</span></p> </div> </div> <div class="element"> <h3>Optical Properties</h3> <div class="element-text"> <p class="NoSpacing"><em>Colour in plane polarised light:</em><span> </span>colourless, pale brown or pale grey<span> </span><br class="NoSpacing" /><em>Pleochroism:</em><span> </span>variable weak to moderate<span> </span><br class="NoSpacing" /><em>Relief:</em><span> </span>moderate<span> </span><br class="NoSpacing" /><em>Birefringence:</em><span> </span>0.018-0.033; 1^st<span> </span>order pink to 2^nd<span> </span>order orange<span> </span><br class="NoSpacing" /><em>Extinction:</em><span> </span>inclined<span> </span><em><br />Twinning:</em><span> </span>simple, common</p> </div> </div> <div class="element"> <h3>Rock Specimens</h3> <div class="element-text"> <p><a href="/p1acollections/exhibits/show/igneous-rocks/l141">L141 Gabbro</a><span> </span><br /><a href="/p1acollections/exhibits/show/igneous-rocks/l161">L161 Basalt, amygdaloidal</a><span> </span><br /><a href="/p1acollections/exhibits/show/igneous-rocks/l162">L162 Basalt, porphyritic</a><span> </span><br /><a href="/p1acollections/exhibits/show/igneous-rocks/l172">L172 Ultramafic cumulate</a></p> </div> </div> <div class="element"> <h3>Advanced Notes</h3> <div class="element-text"> <p class="NoSpacing"><span>Clinopyroxene contains calcium. It encompasses a range of solid solutions from (Mg,Fe)₂[Si₂O₆] to Ca(Mg,Fe)[Si₂O₆]. The physical and optical properties detailed above refer to augite, a clinopyroxene common in mafic igneous rocks.</span></p> </div> </div> <div class="element"> <h3>Mineral Name</h3> <div class="element-text">clinopyroxene<br />augite</div> </div> mafic ultramafic https://wserv3.esc.cam.ac.uk/p1acollections/files/original/3a045ee9b56d4f42ca318e0623d82bac.jpg 9de28fb8f3aa176785607b86ed35a349 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/ad163c9708faad229d3b45dfe05cc6d2.jpg c1d47de48160ed5d95eaa51938891095 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/9a8a6274518a04739a23711773ab19ae.jpg 9d09b58110825fcd56646bf1cec98d2b 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>L172<br /></strong></h2> <h2>Ultramafic cumulate</h2> Subject The topic of the resource <h3>Age</h3> <div class="element-text">Precambrian<br /><br /><h3>Location</h3> <div class="element-text">Lewisian Complex, Dyke<br />Assynt, Sutherland</div> </div> Description An account of the resource <div class="element-set"> <div class="element"> <div class="element-text"> <div class="element"> <div class="element-text five columns omega"> <h3>Hand Specimen</h3> </div> </div> <div class="element"> <div class="element-text five columns omega"> <div class="element-set"> <div class="element"> <div class="element-text">Greenish black, coarse-grained rock, comprising olivine, clinopyroxene and plagioclase.<br />Grains typically 1-2 mm across.<span> </span></div> </div> <div class="element"> <h3>Thin-section</h3> <div class="element-text"> <p>Olivine<span> </span><br />-<span> </span><a href="https://wserv3.esc.cam.ac.uk/p1acollections/items/show/256">Subhedral</a><span> </span>to<span> </span><a href="https://wserv3.esc.cam.ac.uk/p1acollections/items/show/189">euhedral</a><span> </span>grains making up ~45% of the rock.<span> </span><a href="https://wserv3.esc.cam.ac.uk/p1acollections/items/show/170">Alteration</a><span> </span>to magnetite and serpentine, particularly along the curving cracks. Cracks across the thin-section, could be due to expansion of the rock as the olivine was altered.</p> <p>Clinopyroxene<span> </span><br />-<span> </span><a href="https://wserv3.esc.cam.ac.uk/p1acollections/items/show/211">Interstitial</a><span> </span>phase making up ~35% of the rock. Moderate<span> </span><a href="https://wserv3.esc.cam.ac.uk/p1acollections/items/show/247">relief</a>, inclined<span> </span><a href="https://wserv3.esc.cam.ac.uk/p1acollections/items/show/190">extinction</a> and first order pink to second order orange interference colours.</p> <p>Plagioclase feldspar<span> </span><br />- Interstitial phase making up ~20% of the rock. Low first order interference colours and<span> </span><a href="https://wserv3.esc.cam.ac.uk/p1acollections/items/show/169">lamellar twinning</a>.</p> <p>Accessory minerals - Biotite, small, interstitial grains, altered.</p> <p>This is a cumulate rock. It has undergone late-stage shear banding.</p> </div> </div> <div class="element"> <h3>Rock History</h3> <div class="element-text"> <p>Olivine<span> </span><a href="https://wserv3.esc.cam.ac.uk/p1acollections/items/show/236">phenocrysts</a><span> </span>crystallised first.<span> </span><br />Clinopyroxene grew around the olivine phenocrysts.<span> </span><br />Interstitial feldspar filled in the remaining gaps.<span> </span><br />Shearing of the rock produced bands of deformation.<span> </span><br />Hydrothermal alteration.</p> </div> </div> <div class="element"> <h3>Rock Name</h3> <div class="element-text">ultramafic cumulate</div> </div> </div> </div> </div> </div> </div> </div> alteration euhedral interstitial shear ultramafic