24 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>Porphyritic</h2> Subject The topic of the resource <div> <div class="element-set"> <div class="element"> <div class="element-text"> <p>An igneous rock containing phenocrysts in a fine-grained groundmass is said to have a porphyritic texture.</p> </div> </div> </div> </div> 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>Porphyroblast</h2> Subject The topic of the resource <p>A porphyroblast is the metamorphic equivalent of a phenocryst. Do not confuse them! It is a large crystal set into a finer-grained fabric, in a metamorphic rock.</p> Description An account of the resource <div> <div class="element-set"> <div class="element"> <div class="element-text"> <p><em>Compare with<span> </span><a href="https://wserv3.esc.cam.ac.uk/p1acollections/items/show/236">phenocryst</a>.</em></p> </div> </div> </div> </div> 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>Prismatic</h2> Subject The topic of the resource <span>An elongate “pencil-like” crystal habit. Prismatic crystals are wider than acicular crystals.</span> https://wserv3.esc.cam.ac.uk/p1acollections/files/original/39ae47b23110f61dc6a0c406affbbf52.jpg 51f4085ac65b27fbab76ae783f7698e8 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/a80ea2f1702b30aebd3ac07020f12cc1.jpg a9a01f476ba1204e36ea0f961c5793d6 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/0a1c0e8dce3c906fbeeabf056b982815.jpg c0cd2b4702f158ae577237cf1bfb934d 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>Pyrite</h2> Description An account of the resource <div class="element"> <h3>Formula</h3> <div class="element-text">FeS₂</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>pale brassy yellow; black when fine-grained<br /><em>Streak:</em><span> </span>greenish or brownish<br /><em>Lustre:</em><span> </span>metallic<br /><em>Cleavage:</em><span> </span>not obvious<br /><em>Hardness:</em><span> </span>6-6.5</p> </div> </div> <div class="element"> <h3>Optical Properties</h3> <div class="element-text"> <p><em>Colour in plane polarised light:</em><span> </span>opaque</p> </div> </div> <div class="element"> <h3>Mineral Specimens</h3> <div class="element-text"> <p class="NoSpacing"><strong><span>M520 Slate containing pyrite<br class="NoSpacing" /></span>Coniston, Lancashire <span><br class="NoSpacing" /></span></strong>Cubic crystals, embedded in a well-cleaved slate <br class="NoSpacing" />Golden colour <br class="NoSpacing" />Metallic lustre <br />Indistinct cleavage in places</p> <p class="NoSpacing"><strong><span>M412 </span></strong><strong><span>Quartz (with galena and pyrite)</span></strong><span> </span><br class="NoSpacing" /><strong>North Wales</strong><strong></strong><span> </span><br class="NoSpacing" />A mass of small hexagonal quartz prisms, with galena, pyrite and zinc blende.<span> </span><br class="NoSpacing" />Transparent, white to light grey<span> </span><br class="NoSpacing" />Galena: purple-black, shiny, platy habit, metallic<span> </span><br class="NoSpacing" />Pyrite: metallic lustre, gold colour, cubic habit, “Fools’ gold”</p> </div> </div> <div class="element"> <h3>Rock Specimens</h3> <div class="element-text"> <p><a href="/p1acollections/exhibits/show/igneous-rocks/l112">L112 Rhyolite</a><span> </span><br /><a href="/p1acollections/exhibits/show/sedimentary-rocks/l371">L371 Chert, bedded</a></p> </div> </div> <div class="element"> <h3>Mineral Name</h3> <div class="element-text">pyrite<br />opaques</div> </div> cubic felsic gold sedimentary https://wserv3.esc.cam.ac.uk/p1acollections/files/original/0bf5d3a466fa7829e4ef2bdff830625a.jpg 6cd884f723303bde9f49b486c09d2b91 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/26bbd90e23750b6cd8f025a7c4477901.jpg a7e67bd99ca02148d530d0f06a0cc68b https://wserv3.esc.cam.ac.uk/p1acollections/files/original/301029738940ac75d82ed2ef3b0d90b2.jpg a9a01f476ba1204e36ea0f961c5793d6 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/96e67e3861b4a7dcb407f3b5f225bb27.jpg 30e1e24259599004ba7c7f6d73bf6953 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>Quartz</h2> Description An account of the resource <div class="element"> <h3>Formula</h3> <div class="element-text">SiO₂</div> </div> <div class="element"> <h3>Structure</h3> <div class="element-text"> <p>Framework 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>Colour in hand specimen:</em><span> </span>colourless<span> </span><br class="NoSpacing" /><em>Lustre:</em><span> </span>vitreous<span> </span><br class="NoSpacing" /><em>Pleochroism:</em><span> </span>none<span> </span><br class="NoSpacing" /><em>Cleavage:</em><span> </span>none<span> </span><br /><em>Hardness:</em><span> </span>7</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 /><em>Birefringence:</em><span> </span>0.009; 1^st<span> </span>order grey</p> </div> </div> <div class="element"> <h3>Mineral Specimens</h3> <div class="element-text"> <p class="NoSpacing"><strong><span>M410 </span></strong><strong><span>Quartz</span></strong><span> </span><br class="NoSpacing" />Characteristic prismatic crystal form: hexagonal cross-section, needle-like; hexagonal prism surmounted by a hexagonal pyramid<span> </span><br class="NoSpacing" />Colourless, transparent, milky in places<span> </span><br class="NoSpacing" /><strong></strong></p> <p class="NoSpacing"><strong><span>M411 </span></strong><strong><span>Quartz</span></strong><span> </span><br class="NoSpacing" /><strong>Madagascar</strong><strong></strong><span> </span><br class="NoSpacing" />Colourless, transparent quartz fragment, milky due to cracks and crystal boundaries<span> </span><br class="NoSpacing" />Vitreous lustre, conchoidal fracture, no cleavage</p> <p class="NoSpacing"><strong><span>M412 </span></strong><strong><span>Quartz (with galena and pyrite)</span></strong><span> </span><br class="NoSpacing" /><strong>North Wales</strong><strong></strong><span> </span><br class="NoSpacing" />A mass of small hexagonal quartz prisms, with galena, pyrite and zinc blende.<span> </span><br class="NoSpacing" />Transparent, white to light grey<span> </span><br class="NoSpacing" />Galena: purple-black, shiny, platy habit, metallic<span> </span><br class="NoSpacing" />Pyrite: metallic lustre, gold colour, cubic habit, “Fools’ gold”</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/l110">L110 Rhyolite, porphyritic (quartz porphyry)</a><span> </span><br /><a href="/p1acollections/exhibits/show/igneous-rocks/l120">L120 Granodiorite</a><span> </span><br /><a href="/p1acollections/exhibits/show/sedimentary-rocks/l311">L311 Conglomerate, matrix</a><span> </span><br /><a href="/p1acollections/exhibits/show/sedimentary-rocks/l323">L323 Sandstone, arenite</a><span> </span><br /><a href="/p1acollections/exhibits/show/sedimentary-rocks/l370">L370 Chert, flint nodule, cryptocrystalline</a><span> </span><br /><a href="/p1acollections/exhibits/show/metamorphic-rocks/l504">L504 Garnet schist</a><span> </span><br /><a href="/p1acollections/exhibits/show/metamorphic-rocks/l521">L521 Quartzite</a></p> </div> </div> <div class="element"> <h3>Mineral Name</h3> <div class="element-text">silica<br />quartz</div> </div> igneous metamorphic milky sedimentary 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>Relief</h2> Subject The topic of the resource <p>When viewed under plane polarised light, some mineral grains are more clearly defined than others. They have heavier, darker edges. These minerals have higher relief.</p> <p>Relief is determined by the difference in the refractive indices of the grain and mounting medium. The mounting medium typically has a refractive index (R.I., n_i) of ~1.54. A mineral with a low refractive index, such as quartz (R.I., n_i ~1.5) has low relief because it has a refractive index very similar to that of the mounting medium. A mineral with a high refractive index, such as garnet (R.I., n_i ~1.7) has high relief because it has a refractive index much higher than that of the mounting medium.</p> 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>Replacement</h2> Subject The topic of the resource An igneous texture in which a mineral grain is resorbed and a later crystallising phase grows in its place. 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>Resinous [lustre]</h2> Subject The topic of the resource <div> <div class="element-set"> <div class="element"> <div class="element-text"> <p>Minerals displaying the lustre of resin or of smooth-surfaced plastic are described as resinous. Amber, for example, has resinous lustre.</p> </div> </div> </div> </div> <div> <div class="element"> <div class="element-text"></div> <div class="collection"></div> </div> </div> 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>Rhombohedral cleavage</h2> Subject The topic of the resource <p>Three intersecting cleavage planes. A mineral with rhombohedral cleavage will break up along its cleavage planes into perfect rhombohedra. Calcite, for example, has rhombohedral cleavage.</p> Description An account of the resource <em>Have a look at <strong><a href="https://wserv3.esc.cam.ac.uk/p1acollections/items/show/64">calcite</a> (M540, M541, M542)</strong> in the 1A Reference Collection.</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>Schistosity</h2> Subject The topic of the resource Schistosity is a type of foliation (planar fabric) found within metamorphosed rocks. It is produced under moderate metamorphic conditions by the alignment and significant recrystallisation of mineral grains. Recrystallised grains are large enough to be seen with the naked eye.