21 10 264 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/. Description An account of the resource This glossary describes a number of geological terms with which the 1A students should become familiar.<span> It is by no means an exhaustive list, but is aimed to help you understand the material within the first year course.</span> Title A name given to the resource Glossary 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>Lustre</h2> Subject The topic of the resource A combination of the intensity and quality of the light reflected from the surface of a mineral. A number of terms are used to describe the range of lustres displayed by minerals, including adamantine, dull, metallic, pearly, resinous and vitreous. 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/. Description An account of the resource This glossary describes a number of geological terms with which the 1A students should become familiar.<span> It is by no means an exhaustive list, but is aimed to help you understand the material within the first year course.</span> Title A name given to the resource Glossary 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>Macrocryst</h2> Subject The topic of the resource A relatively large crystal, usually occurring within an igneous rock. Unlike the term phenocryst, it does not imply a petrogenetic link between the crystal and the surrounding magma. Description An account of the resource <em>Compare with<span> </span><a href="https://wserv3.esc.cam.ac.uk/p1acollections/items/show/236">phenocryst</a>.</em> https://wserv3.esc.cam.ac.uk/p1acollections/files/original/3609ef5a5513cbf5914369118a83e223.jpg 37e8768bf174c1964fad35943172adcd https://wserv3.esc.cam.ac.uk/p1acollections/files/original/876136d4968a419d4264dca9fc74aad8.jpg 87a4d2250300ccf7b8355307ce0a356a https://wserv3.esc.cam.ac.uk/p1acollections/files/original/7c5c1965751afc7caa43cb98b132ac56.jpg 0e28846df3f83b9f340589ac0481908d 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>Magnetite</h2> Subject The topic of the resource <div class="element-set"> <div class="element"> <div class="element-text"> <p>Magnetite is the most abundant oxide in igneous rock.</p> </div> </div> </div> Description An account of the resource <div class="element"> <h3>Formula</h3> <div class="element-text"> <p>Fe₃O₄</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>cubic</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>Streak:</em><span> </span>black<br /><em>Cleavage:</em><span> </span>none<br /><em>Hardness:</em><span> </span>7.5-8</p> </div> </div> <div class="element"> <h3>Optical Properties</h3> <div class="element-text"> <p><em>Colour in plane polarised light:</em><span> </span>almost opaque<br /><em>Relief:</em><span> </span>high<br />Isotropic</p> </div> </div> <div class="element"> <h3>Mineral Specimens</h3> <div class="element-text"> <p class="NoSpacing"><strong><span>M501 </span></strong><strong><span>Magnetite</span></strong><span> </span><br class="NoSpacing" /><strong>Brazil</strong><strong></strong><span> </span><br class="NoSpacing" />Crystals showing the characteristic octahedral form<span> </span><br class="NoSpacing" />Silver-black colour<span> </span><br class="NoSpacing" />Metallic lustre</p> <p class="NoSpacing"><strong><span>M502 </span></strong><strong><span>Magnetite</span></strong><span> </span><br class="NoSpacing" /><strong>Hay Tor, Devon</strong><strong></strong><span> </span><br class="NoSpacing" />A mass of small octahedral crystals embedded in a metamorphic rock<span> </span><br class="NoSpacing" />Silver-black<span> </span><br class="NoSpacing" />Metallic lustre<span> </span><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/l102">L102 Hornblende biotite granite</a><br /><a href="/p1acollections/exhibits/show/igneous-rocks/l120">L120 Granodiorite, accessory</a><span> </span><br /><a href="/p1acollections/exhibits/show/igneous-rocks/l141">L141 Gabbro, olivine decomposition, accessory</a><span> </span><br /><a href="/p1acollections/exhibits/show/igneous-rocks/l162">L162 Basalt, porphyritic, feldspar inclusion</a><span> </span><br /><a href="/p1acollections/exhibits/show/igneous-rocks/l172">L172 Ultramafic cumulate, olivine alteration</a></p> </div> </div> <div class="element"> <h3>Mineral Name</h3> <div class="element-text">magnetite<br />iron oxide<br />opaques</div> </div> igneous 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/. Description An account of the resource This glossary describes a number of geological terms with which the 1A students should become familiar.<span> It is by no means an exhaustive list, but is aimed to help you understand the material within the first year course.</span> Title A name given to the resource Glossary 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>Melanocratic</h2> Subject The topic of the resource Melanocratic rocks have a high colour index. That is to say that 60-90 vol% of the rock is made up of ferromagnesian minerals. 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/. Description An account of the resource This glossary describes a number of geological terms with which the 1A students should become familiar.<span> It is by no means an exhaustive list, but is aimed to help you understand the material within the first year course.</span> Title A name given to the resource Glossary 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>Mesocratic</h2> Subject The topic of the resource Mesocratic rocks have a moderate colour index. That is to say that 30-60 vol% of the rock is made up of ferromagnesian minerals. 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/. Description An account of the resource This glossary describes a number of geological terms with which the 1A students should become familiar.<span> It is by no means an exhaustive list, but is aimed to help you understand the material within the first year course.</span> Title A name given to the resource Glossary 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>Metallic [lustre]</h2> Subject The topic of the resource Minerals displaying a metal-like lustre are described as metallic. These minerals have surfaces which are perfectly reflective. Pyrite, for example, has metallic lustre. Description An account of the resource <em>Have a look at <strong>pyrite (<a href="https://wserv3.esc.cam.ac.uk/p1acollections/items/show/60">M520</a>)</strong> in the 1A Reference Series.</em> https://wserv3.esc.cam.ac.uk/p1acollections/files/original/20b9609f2cc656507a1fec2347d9df89.jpg fa472417a23e56ecbb9b556d05c4ffca https://wserv3.esc.cam.ac.uk/p1acollections/files/original/3404979c4792fa74731a7e04e3022017.jpg 599a58e88705064fd972b61f03d15f68 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/65c206021f6f75651f1697f0cd29cf1d.jpg 06b1f7e0df480b95e954641fe6339f67 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>Mica, biotite</h2> Description An account of the resource <div class="element"> <h3>Formula</h3> <div class="element-text">K₂(Mg,Fe²⁺)_6-4(Fe³⁺,Al,Ti)_0-2[Si_6-5Al_2-3O₂₀](OH,F)₄</div> </div> <div class="element"> <h3>Structure</h3> <div class="element-text"> <p>Sheet silicate</p> </div> </div> <div class="element"> <h3>Crystal System</h3> <div class="element-text"> <p class="NoSpacing"><em><span>Crystal</span></em><em><span> system:</span></em><span> monoclinic (-)</span></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> brown or black</span><span> </span><br class="NoSpacing" /><em><span>Cleavage:</span></em><span> one, good</span><span> </span><br class="NoSpacing" /><em><span>Hardness:</span></em><span> 2-3</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> pale yellow, pale green, green or brown</span><span> </span><br /><em><span>Pleochroism:</span></em><span> strong</span><span> </span><br /><em><span>Relief:</span></em><span> low</span><span> </span><br /><em><span>Birefringence: </span></em><span>0.028-0.08; 2^nd order green-yellow to &gt;4^th order</span><span> </span><em><span><br />Extinction: </span></em><span>straight</span></p> </div> </div> <div class="element"> <h3>Mineral Specimens</h3> <div class="element-text"> <p class="NoSpacing"><strong><span>M303 </span></strong><strong><span>Mica, biotite</span></strong><span> </span><br class="NoSpacing" /><strong>Cornwall</strong><strong></strong><span> </span><br class="NoSpacing" />Large irregular biotite crystals in a feathery arrangement<span> </span><br class="NoSpacing" />Dark brown / black / golden<span> </span><br class="NoSpacing" />Metallic lustre<span> </span><br class="NoSpacing" />Platy habit due to the single perfect cleavage</p> <p class="NoSpacing"><strong><span>M304 </span></strong><strong><span>Mica, biotite</span></strong><span> </span><br class="NoSpacing" /><strong>Orlando</strong><strong>, Canada</strong><strong></strong><span> </span><br class="NoSpacing" />Irregular plates of biotite split along cleavage planes<span> </span><br class="NoSpacing" />One good cleavage<span> </span><br class="NoSpacing" />Brilliant metallic lustre</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><span> </span><br /><a href="/p1acollections/exhibits/show/igneous-rocks/l101">L101 Granite</a><span> </span><br /><a href="/p1acollections/exhibits/show/igneous-rocks/l102">L102 Hornblende biotite granite</a><span> </span><br /><a href="/p1acollections/exhibits/show/igneous-rocks/l120">L120 Granodiorite</a><span> </span><br /><a href="/p1acollections/exhibits/show/igneous-rocks/l130">L130 Andesite, porphyritic (porphyrite)</a><span> </span><br /><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">mica<br />biotite</div> </div> basal cleavage igneous metapelite https://wserv3.esc.cam.ac.uk/p1acollections/files/original/f45fcf901e391b706d58c5a76ce9e0f7.jpg 0b887bd5e1ae09a04261e9bb9af69078 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/daa51ed8284e2f268043c893ed2835dc.jpg 1c07f39572ce1f39720e395b2d729c83 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/f85892ba7ce86764f8dafc18adab40a6.jpg e9b02c931f4847fb3d65e56480cc42d2 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>Mica, muscovite</h2> Description An account of the resource <div class="element"> <h3>Formula</h3> <div class="element-text">K₂Al₄[Si₆Al₂O₂₀](OH,F)₄</div> </div> <div class="element"> <h3>Structure</h3> <div class="element-text"> <p>Sheet silicate</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 class="NoSpacing"><em><span>Colour in hand specimen:</span></em><span> colourless</span><span> </span><br class="NoSpacing" /><em><span>Cleavage:</span></em><span> one, good</span><span> </span><br class="NoSpacing" /><em><span>Hardness:</span></em><span> 2.5-3</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<span> </span><br class="NoSpacing" /><em>Pleochroism:</em><span> </span>none<span> </span><br class="NoSpacing" /><em>Relief:</em><span> </span>low<span> </span><br class="NoSpacing" /><em>Birefringence:<span> </span></em>0.036-0.049; 2^nd<span> </span>order pink to 3^rdorder yellow<span> </span><br /><em>Extinction: </em>straight</p> </div> </div> <div class="element"> <h3>Mineral Specimens</h3> <div class="element-text"> <p class="NoSpacing"><strong><span>M301 </span></strong><strong><span>Mica, muscovite</span></strong><span> </span><br class="NoSpacing" /><strong>Lincoln County</strong><strong>, North Carolina</strong><strong></strong><span> </span><br class="NoSpacing" />Well-formed tabular crystals showing the pseudohexangonal symmetry<span> </span><br class="NoSpacing" />Colourless, mirror- like, metallic lustre<span> </span><br class="NoSpacing" />Platy, flaky habit<span> </span><br class="NoSpacing" />Soft</p> <p class="NoSpacing"><strong><span>M302 </span></strong><strong><span>Mica, muscovite</span>   <span> </span></strong><br class="NoSpacing" /><strong>Mysore</strong><strong>, India</strong><strong></strong><span> </span><br class="NoSpacing" />Plates of mica artificially cut to shape<span> </span><br class="NoSpacing" />Colourless<span> </span><br class="NoSpacing" />One perfect cleavage</p> </div> </div> <div class="element"> <h3>Rock Specimens</h3> <div class="element-text"> <p><a href="/p1acollections/exhibits/show/igneous-rocks/l110">L110 Rhyolite, porphyritic (quartz porphyry)</a><span> </span><br /><a href="/p1acollections/exhibits/show/volcaniclastic-rocks/l201">L201 Tuff</a><span> </span><br /><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">mica<br />muscovite</div> </div> basal cleavage igneous metapelite 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/. Description An account of the resource This glossary describes a number of geological terms with which the 1A students should become familiar.<span> It is by no means an exhaustive list, but is aimed to help you understand the material within the first year course.</span> Title A name given to the resource Glossary 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>Micaceous</h2> Subject The topic of the resource A rock containing a significant proportion of micas is described as micaceous. The micas are a group of sheet silicate minerals, which include biotite and muscovite. Description An account of the resource <em>Have a look at <strong><a href="https://wserv3.esc.cam.ac.uk/p1acollections/items/show/51">muscovite mica</a> (M301, M302) </strong>and <strong><a href="https://wserv3.esc.cam.ac.uk/p1acollections/items/show/52">biotite mica</a> (M303, M304)</strong> in the 1A Reference Series.</em> 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/. Description An account of the resource This glossary describes a number of geological terms with which the 1A students should become familiar.<span> It is by no means an exhaustive list, but is aimed to help you understand the material within the first year course.</span> Title A name given to the resource Glossary 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>Microcline twinning</h2> Description An account of the resource <em>See<span> </span><a href="https://wserv3.esc.cam.ac.uk/p1acollections/items/show/183">cross-hatched twins</a>.</em>