23 10 264 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/6a2fdeca2774e679a0153821edf123e9.jpg 6a17bfc2d428df30b504c9506a7bb23a https://wserv3.esc.cam.ac.uk/p1acollections/files/original/2711ba062a08634b610c1cdd18f67fcc.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>Orthopyroxene</h2> Description An account of the resource <div class="element"> <h3>Formula</h3> <div class="element-text">(Mg,Fe)₂Si₂O₆</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 system:</em><span> </span>orthorhombic (+) (-)</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><br class="NoSpacing" /><em><span>Cleavage:</span></em><span> two at 90°</span><span> </span><br class="NoSpacing" /><em><span>Hardness:</span></em><span> 5-6</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>colourless, reddish or greenish </span><br class="NoSpacing" /><em><span>Pleochroism:</span></em><span> variable weak to strong</span><span> </span><br class="NoSpacing" /><em><span>Relief:</span></em><span> moderate </span><br class="NoSpacing" /><em><span>Birefringence:</span></em><span> 0.007-0.020; 1^st order grey to 2^nd order purple</span><span> </span><br class="NoSpacing" /><em><span>Extinction: </span></em><span>straight</span></p> </div> </div> <div class="element"> <h3>Advanced Notes</h3> <div class="element-text"> <p class="NoSpacing"><span>Orthopyroxene has two end-member compositions: enstatite, Mg₂Si₂O₆, and ferrosilite, Fe²⁺₂Si₂O₆.</span></p> </div> </div> <div class="element"> <h3>Mineral Name</h3> <div class="element-text">orthopyroxene</div> </div> mafic https://wserv3.esc.cam.ac.uk/p1acollections/files/original/12b5c18a74215d375e002f21037f4df9.jpg 113d76f170e53159aa1248482d0c7b82 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>Tourmaline</h2> Subject The topic of the resource <span>Tourmaline is the only common mineral of which boron is an essential constituent. Its presence in a rock, therefore, indicates that the rock contains significant boron. </span> Description An account of the resource <div class="element"> <h3>Formula</h3> <div class="element-text">(Na,Ca)(Mg,Fe,Mn,Li,Al)₃(Al,Mg,Fe³⁺)₆[Si₆O₁₈](BO₃)₃(O,OH)₃(OH,F)</div> </div> <div class="element"> <h3>Structure</h3> <div class="element-text"> <p>Ring 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><em>Colour in hand specimen:</em><span> </span>black<br /><em>Hardness:</em><span> </span>7</p> </div> </div> <div class="element"> <h3>Optical Properties</h3> <div class="element-text"> <p><em>Colour in plane polarised light:</em><span> </span>typically brown-green or green<br /><em>Pleochroism:</em><span> </span>strongly pleochroic in many colours<br /><em>Relief:</em><span> </span>moderate<br /><em>Birefringence:</em><span> </span>typically 2nd order</p> </div> </div> <div class="element"> <h3>Rock Specimens</h3> <div class="element-text"> <p><a href="/p1acollections/exhibits/show/metamorphic-rocks/l504">L504 Garnet schist</a></p> </div> </div> <div class="element"> <h3>Mineral Name</h3> <div class="element-text">tourmaline</div> </div> granite metapelite pegmatite https://wserv3.esc.cam.ac.uk/p1acollections/files/original/b8b233edb6e035dc684e24f4623b773c.jpg eccd6795baa14b8a4a88173b5a20e307 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>Epidote</h2> Description An account of the resource <div class="element"> <h3>Formula</h3> <div class="element-text">Ca₂Al₂O∙(Al,Fe³⁺)OH[Si₂O₇][SiO₄]</div> </div> <div class="element"> <h3>Structure</h3> <div class="element-text"> <p>Orthosilicate</p> </div> </div> <div class="element"> <h3>Crystal System</h3> <div class="element-text"> <p><em>Crystal system:</em><span> </span>monoclinic (-)</p> </div> </div> <div class="element"> <h3>Physical Properties</h3> <div class="element-text"> <p><em>Colour in hand specimen:</em><span> </span>green<br /><em>Cleavage:</em><span> </span>one, perfect<br /><em>Hardness:</em><span> </span>6</p> </div> </div> <div class="element"> <h3>Optical Properties</h3> <div class="element-text"> <p><em>Colour in plane polarised light:</em><span> </span>yellow-green<br /><em>Pleochroism:</em><span> </span>yes<br /><em>Relief:</em><span> </span>high<br /><em>Birefringence:</em><span> </span>0.015-0.051; 1st order orange to 3rd order pink<br /><em>Extinction:</em><span> </span>inclined<br /><em>Twinning:</em><span> </span>lamellar, not common</p> </div> </div> <div class="element"> <h3>Rock Specimens</h3> <div class="element-text"> <p><a href="/p1acollections/exhibits/show/sedimentary-rocks/l354">L354 Limestone, shelly</a></p> </div> </div> <div class="element"> <h3>Mineral Name</h3> <div class="element-text">epidote</div> </div> low grade medium grade secondary https://wserv3.esc.cam.ac.uk/p1acollections/files/original/74710dbf85be2a6e9e238ba537ef6ad4.jpg 28595880e272b17b8a23671cdc97d677 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>Garnet</h2> Description An account of the resource <div class="element"> <h3>Formula</h3> <div class="element-text">(Mg,Fe,Ca)₃Al₂Si₃O₁₂</div> </div> <div class="element"> <h3>Structure</h3> <div class="element-text"> <p>Orthosilicate</p> </div> </div> <div class="element"> <h3>Crystal System</h3> <div class="element-text"> <p><em>Crystal system:</em><span> </span>cubic</p> </div> </div> <div class="element"> <h3>Physical Properties</h3> <div class="element-text"> <p><em>Colour in hand specimen:</em><span> </span>typically red<br /><em>Cleavage:</em><span> </span>none<br /><em>Hardness:</em><span> </span>6-7.5</p> </div> </div> <div class="element"> <h3>Optical Properties</h3> <div class="element-text"> <p><em>Colour in plane polarised light:</em><span> </span>colourless, pale pink<span> </span><br /><em>Pleochroism:</em><span> </span>none<br /><em>Relief:</em><span> </span>high<br />Isotropic</p> </div> </div> <div class="element"> <h3>Mineral Specimens</h3> <div class="element-text"> <p><span><strong>M130 Garnet schist</strong></span><br /><strong>Portsoy, Banffshire</strong><br />Euhedral porphyroblasts of dark-red garnet, with quartz, mica and other minerals in a medium-grade metamorphic rock.</p> </div> </div> <div class="element"> <h3>Rock Specimens</h3> <div class="element-text"> <p><a href="/p1acollections/exhibits/show/metamorphic-rocks/l504">L504 Garnet schist</a></p> </div> </div> <div class="element"> <h3>Advanced Notes</h3> <div class="element-text"> <p>The garnet group encompasses a wide range of compositions, and consequently a range of optical and physical properties. The properties detailed above are typical of pyrope (Mg₃Al₂Si₃O₁₂), almandine (Fe²⁺₃Al₂Si₃O₁₂) and grossular (Ca₃Al₂Si₃O₁₂).</p> </div> </div> <div class="element"> <h3>Mineral Name</h3> <div class="element-text">garnet</div> </div> metamorphism metapelite https://wserv3.esc.cam.ac.uk/p1acollections/files/original/8d7c5ffdcaf046d54625d611965a68ea.jpg e2278fe00dca61288a4107247a76bbad 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>Sphene<strong> (titanite)</strong></h2> Description An account of the resource <div class="element"> <h3>Formula</h3> <div class="element-text">CaTi[SiO₄](O, OH, F)</div> </div> <div class="element"> <h3>Structure</h3> <div class="element-text"> <p>Orthosilicate</p> </div> </div> <div class="element"> <h3>Crystal System</h3> <div class="element-text"> <p><em>Crystal system:</em><span> </span>monoclinic (+)</p> </div> </div> <div class="element"> <h3>Physical Properties</h3> <div class="element-text"> <p><em>Colour in hand specimen:</em><span> </span>colourless, yellow, green, brown or black<br /><em>Cleavage:</em><span> </span>one, good<br /><em>Hardness:</em><span> </span>5</p> </div> </div> <div class="element"> <h3>Optical Properties</h3> <div class="element-text"> <p><em>Colour in plane polarised light:</em><span> </span>colourless, yellow or typically brown<br /><em>Pleochroism:</em><span> </span>moderate if coloured<br /><em>Relief:</em><span> </span>high<br /><em>Birefringence:</em><span> </span>0.100-0.192; &gt;4th order<br /><em>Extinction:</em><span> </span>inclined<br /><em>Twinning:</em><span> </span>simple twins; occasionally lamellar twins</p> </div> </div> <div class="element"> <h3>Rock Specimens</h3> <div class="element-text"> <p><a href="/p1acollections/exhibits/show/igneous-rocks/l101">L101 Granite</a><span> </span><br /><a href="/p1acollections/exhibits/show/igneous-rocks/l120">L120 Granodiorite</a></p> </div> </div> <div class="element"> <h3>Mineral Name</h3> <div class="element-text">sphene<br />titanite<br /><h3>Advanced notes</h3> <div class="element-text">Diamond shaped cross sections are common<br /><br /></div> </div> </div> https://wserv3.esc.cam.ac.uk/p1acollections/files/original/5e37a66fc246f7e8a088a4e4c0d011bd.jpg 541861a9fa9a4ae459f66f0e9c425bb3 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>Zircon</h2> Description An account of the resource <div class="element-set"> <div class="element"> <div class="element-text"> <h3>Formula</h3> </div> </div> </div> <div class="element-set"> <div class="element"> <div class="element-text">Zr[SiO₄]</div> </div> <div class="element"> <h3>Structure</h3> <div class="element-text"> <p>Orthosilicate</p> </div> </div> <div class="element"> <h3>Crystal System</h3> <div class="element-text"> <p><em>Crystal system:</em><span> </span>tetragonal (+)</p> </div> </div> <div class="element"> <h3>Physical Properties</h3> <div class="element-text"> <p><em>Colour in hand specimen:</em><span> </span>reddish brown, yellow, grey, green or colourless<br /><em>Hardness:</em><span> </span>7.5</p> </div> </div> <div class="element"> <h3>Optical Properties</h3> <div class="element-text"> <p><em>Colour in plane polarised light:</em> colourless to pale brown<span> </span><br /><em>Pleochroism:</em> very weak<br /><em>Relief:</em> high<br /><em>Birefringence:</em> 0.042-0.065; 3rd order green to 4th order green<br /><em>Extinction:</em> straight<br /><em>Twinning:</em> rare</p> </div> </div> <div class="element"> <h3>Rock Specimens</h3> <div class="element-text"> <p><a href="/p1acollections/exhibits/show/igneous-rocks/l100">L100 Alkali granite</a></p> </div> </div> <div class="element"> <h3>Mineral Name</h3> <div class="element-text">zircon</div> </div> </div> Subject The topic of the resource Zircon is a common accessory mineral of many igneous rocks. Pleochroic haloes are formed by damage to the crystal lattice of enclosing minerals by the radioactive decay of elements such as Th and U in zircon. These may be particularly noticeable in biotite grains in old granitic rocks. granite radiation thorium uranium https://wserv3.esc.cam.ac.uk/p1acollections/files/original/c48647ef4bdeaab9cd06257b506e7ba5.jpg 9f81309144388bca4172f5e94f4d8974 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/1bccc279a78201775346b3920b73c491.jpg bc43e3bafb84ae9faba453d6169d411a 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>Olivine</h2> Description An account of the resource <div class="element"> <h3>Formula</h3> <div class="element-text">(Mg,Fe)₂[SiO₄]</div> </div> <div class="element"> <h3>Structure</h3> <div class="element-text"> <p>Orthosilicate</p> </div> </div> <div class="element"> <h3>Crystal System</h3> <div class="element-text"> <p><em>Crystal system:</em><span> </span>orthorhombic (+) (-)</p> </div> </div> <div class="element"> <h3>Physical Properties</h3> <div class="element-text"> <p><em>Colour in hand specimen:</em> pale green<br /><em>Cleavage: </em>none, instead it has characteristic curving cracks<em><br />Hardness:</em> 7</p> </div> </div> <div class="element"> <h3>Optical Properties</h3> <div class="element-text"> <p><em>Colour in plane polarised light:</em> colourless<br /><em>Relief:</em> moderate <br /><em>Birefringence:</em> 0.035; 2nd order pink</p> </div> </div> <div class="element"> <h3>Mineral Specimens</h3> <div class="element-text"> <p><strong><span>M100 Olivine</span><span> </span><br />North Carolina</strong><span> </span><br />A mass of rather irregular crystals of olivine<br />Yellow-green colour<br />Vitreous lustre<br />No cleavage</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/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">Olivine has two end-member compositions: forsterite, Mg₂[SiO₄], and fayalite, Fe₂[SiO₄]. The physical and optical properties detailed above refer to forsterite<strong>.</strong><span> </span>Forsteritic olivine is a common constituent of mafic and ultra-mafic rocks.<br />Cracks are often filled with serpentinite alteration.</div> </div> <div class="element"> <h3>Mineral Name</h3> <div class="element-text">olivine<br />forsterite<br />fayallite</div> </div> mafic https://wserv3.esc.cam.ac.uk/p1acollections/files/original/a7df9ee4ba246ad0597901f02ce9248e.jpg c00e1ed63dab525439bafbcd93e404ad https://wserv3.esc.cam.ac.uk/p1acollections/files/original/a96297a90c4701546417a62762349b0c.jpg 10d02e1fb68349bfd8e84366835b2ca5 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/5ef179694fabe2f138284ddd124cda39.jpg 712079ecee63ba6327aad3a1eddff03e 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>L521<br /></strong></h2> <h2>Quartzite</h2> Subject The topic of the resource <h3>Age</h3> <div class="element-text"> <p>Precambrian</p> <h3>Location</h3> <div class="element-text"> <p>Braemar, Aberdeenshire</p> </div> </div> Description An account of the resource <div class="element"> <div class="element"> <h3>Hand Specimen</h3> <div class="element-text"> <p>Buff coloured rock.<br />Almost pure quartz, which has been very well recrystallised.<br />Faint banding could be original bedding.</p> </div> </div> <div class="element"> <h3>Thin-section</h3> <div class="element-text"> <p>Fine to medium grained recrystallised quartz with<span> </span><a href="/p1acollections/items/show/257">sutured contacts</a>.</p> </div> </div> <div class="element"> <h3>Rock History</h3> <div class="element-text"> <p>The sutured (ragged) grain boundaries and<span> </span><a href="/p1acollections/items/show/263">undulose extinction</a><span> </span>of the quartz grains indicate that this rock formed under relatively low temperature metamorphism. Had the rock been raised to higher temperatures perfect 120° grain boundaries would have formed, and the quartz would not be strained.</p> <p class="NoSpacing">Inserting the sensitive tint plate results in the vast majority of grains changing colour in the same way – most of the grains simultaneously display higher interference colours in one orientation, and lower interference colours in the other orientation. This strong<span> </span><a href="/p1acollections/items/show/192">fabric</a><span> </span>was produced by recrystallisation under directed stress, which caused all the grains to elongate in one direction. </p> </div> </div> <div class="element"></div> <div class="element"> <h3>Rock Name</h3> <div class="element-text">quartzite</div> </div> </div> banding foliation suture https://wserv3.esc.cam.ac.uk/p1acollections/files/original/d3eb994c3d6575e87d3c2adcbe5e5671.jpg 2a16c884a7af786c6616089ae2bc1421 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/acdbe621cb181f8585188f05bae056ad.jpg d92f142e31dd65ca4db820ec44f62f08 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/d1c6257526bc338ea4213e11d7061ba8.jpg 9b3c3e978edb4fab3ca1d81922539629 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>L520<br /></strong></h2> <h2>Quartzite</h2> Subject The topic of the resource <h3>Specimen Age</h3> <div class="element-text"> <p>Carboniferous</p> <h3>Location</h3> <div class="element-text"> <p>Coal measures<br />Corrie, Arran</p> </div> </div> Description An account of the resource <div class="element"> <h3>Hand Specimen</h3> <div class="element-text"> <p>Almost entirely made up of fine sand sized quartz grains. Does not fizz with acid, so no carbonate present. Clean white rock, apart from pink-brown weathering. Dark carbonaceous marks are plant roots.</p> </div> </div> <div class="element"> <h3>Thin-section</h3> <div class="element-text"> <p>Subangular quartz grains, typically 0.25 mm across with<span> </span><a href="/p1acollections/items/show/257">sutured contacts</a>.</p> </div> </div> <div class="element"> <h3>Rock History</h3> <div class="element-text">The sutured contacts between the quartz grains indicate that this rock has been metamorphosed to a quartzite. This is a very well recrystallised rock. The protolith was a fine-grained quartz arenite (&lt;15% matrix), but we cannot tell how angular or spherical the original grains were as they have been partially dissolved by pressure solution to form sutured contacts.</div> </div> <div class="element"></div> <div class="element"></div> <div class="element"> <h3>Rock Name</h3> <div class="element-text">quartzite</div> </div> suture https://wserv3.esc.cam.ac.uk/p1acollections/files/original/57eb9d161e24081334fddcaa5522b630.jpg 98a53ec0911ccd3ce20f1096608dfa02 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/e148827aaff78a32a6daf8c169fa2639.jpg 575620169218ba18643aec7f3f6febf5 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/4441d696cc8b2928132fa37dbd6d8e4f.jpg e12bf8a89562af01f31acbf211a2e14f 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>L504</strong></h2> <h2>Garnet schist</h2> Subject The topic of the resource <h3>Age</h3> <div class="element-text"> <p>Pre-Devonian</p> <h3>Location</h3> <div class="element-text"> <p>Ny-Friesland, Spitsbergen</p> </div> </div> Description An account of the resource <div class="element"> <div class="element"> <h3>Hand Specimen</h3> <div class="element-text"> <p>Strongly developed planar<span> </span><a href="/p1acollections/items/show/192">fabric</a><span> </span>made up of<span> </span><a href="/p1acollections/items/show/237">platy</a><span> </span>biotite mica and muscovite mica grains and lenses of quartz grains. Fabric wraps around large,<span> </span><a href="/p1acollections/items/show/189">euhedral</a><span> </span>garnets, typically ~2mm across. Quartz, the most soluble mineral, has recrystallised at the corners of the “eyes”, in the pressure shadows of the garnets.</p> </div> </div> <div class="element"> <h3>Thin-section</h3> <div class="element-text"> <p>Bands of interlocking quartz grains and some feldspar (plagioclase and alkali,<span> </span><a href="/p1acollections/items/show/169">lamellar twinning</a><span> </span>and<span> </span><a href="/p1acollections/items/show/170">alteration</a>), alternate with bands composed of needles of biotite mica and muscovite mica, about 50:50.</p> <p>Quartz displays<span> </span><a href="/p1acollections/items/show/263">undulose extinction</a>, and being the most soluble mineral in this rock has recrystallised into the pressure shadows around the garnets.</p> <p>The fabric is interrupted by large<span> </span><a href="/p1acollections/items/show/189">euhedral</a><span> </span>garnet crystals. Characteristically the garnets are<span> </span><a href="/p1acollections/items/show/213">isotropic</a><span> </span>and have high<span> </span><a href="/p1acollections/items/show/247">relief</a>. They contain<span> </span><a href="/p1acollections/items/show/210">inclusions</a><span> </span>of quartz and mica.</p> <p>Accessory minerals:<span> </span><br />- chlorite<span> </span><br />-<span> </span><span>staurolite</span><span> </span><br />- tourmaline</p> </div> </div> <div class="element"> <h3>Rock History</h3> <div class="element-text"> <p>This schist contains large quantities of muscovite indicating that it had a pelitic protolith. This pelite was subjected to high pressures and temperatures during regional metamorphism, resulting in the crystallisation and alignment of metamorphic minerals.</p> <p>The<span> </span><a href="/p1acollections/items/show/198">foliation</a><span> </span>of this schist may be due to original compositional banding in the pelite; the quartz-rich layers having been sandy layers, while the mica-rich layers were muddy.</p> <p>Some evidence for post-metamorphic deformation: quartz displaying undulose extinction; micas are wrapped around the garnet grains.</p> <p>Tiny grains of chlorite found around the edges of the garnets indicate that some retrogradation has taken place. Chlorite is a common break-down product of garnets.</p> </div> </div> <div class="element"> <h3>Advanced Notes</h3> <div class="element-text"> <p>In thin-section<span> </span><span>staurolite</span><span> </span>is pale-golden in colour. It has high relief, and displays straight<span> </span><a href="/p1acollections/items/show/190">extinction</a><span> </span>and 1st order birefringence colours.</p> </div> </div> <div class="element"></div> <div class="element"></div> <div class="element"> <h3>Rock Name</h3> <div class="element-text">garnet schist</div> </div> </div> fabric foliation metapelite