1 10 7 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/2b220318e8337f2ccddde4e3a52736b2.jpg c9f964a85e0bce7a4ae84d76bd8885d9 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>Apatite</h2> Description An account of the resource <div class="element"> <div class="element"> <h3>Formula</h3> <div class="element-text">Ca₅(PO₄)₃(OH,F,Cl)</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>hexagonal (-)</p> </div> </div> <div class="element"> <h3>Physical Properties</h3> <div class="element-text"> <p><em>Colour in hand specimen:</em><span> </span>green, white, yellow, blue brown etc.<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>generally colourless<br /><em>Pleochroism:</em><span> </span>weak to moderate in coloured varieties<br /><em>Relief:</em><span> </span>moderate<br /><em>Birefrinence:</em><span> </span>0.001-0.007; first order greys<br /><em>Extinction:</em><span> </span>straight<br /><em>Form:</em><span> </span>commonly hexagonal in cross-section</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/l120">L120 Granodiorite</a><span> </span><br /><a href="/p1acollections/exhibits/show/igneous-rocks/l130">L130 Andesite, porphyritic (porphyrite)</a></p> </div> </div> <div class="element"> <h3>Mineral Name</h3> <div class="element-text">apatite</div> </div> </div> igneous volatile 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 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 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/2f7362a5c5cc5e00bc17ca856238ee37.jpg 44db79a97ef535c74d897e9db008bca0 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/94761134fac46b7078906210b5bb3b8f.jpg 323c8b77db6400b701b97ff8bcaa92f2 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/de6097beca8b60a758b218148982f48d.jpg cc38a8962e52d9ea6bf655b0c40038cd 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>Plagioclase feldspar</h2> Description An account of the resource <div class="element"> <h3>Formula</h3> <div class="element-text"> <p>Na[AlSi₃O₈] – Ca[Al₂Si₂O₈]</p> </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>triclinic (+) (-)</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> white</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> 6-6.5</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:</em><span> </span>~0.010, 1^st<span> </span>order grey<span> </span><br class="NoSpacing" /><em>Extinction:</em><span> </span>inclined<span> </span><br class="NoSpacing" /><em>Twinning:</em><span> </span>lamellar, very common</p> </div> </div> <div class="element"> <h3>Mineral Specimens</h3> <div class="element-text"> <p class="NoSpacing"><strong><span>M403 </span></strong><strong><span>Plagioclase feldspar, oligoclase</span></strong><span> </span><br class="NoSpacing" /><strong>Ytterby</strong><strong>, Sweden</strong><strong></strong><span> </span><br class="NoSpacing" />A cleavage fragment of white plagioclase feldspar<span> </span><br class="NoSpacing" />Pearly lustre on cleavage planes<span> </span><br class="NoSpacing" />Two sets of cleavage at 90°<span> </span><br class="NoSpacing" />Fine parallel striations due to lamellar twinning</p> <p class="NoSpacing"><strong><span>M404 </span></strong><strong><span>Plagioclase feldspar, labradorite</span></strong><span> </span><br class="NoSpacing" /><strong>Labrador</strong><strong></strong><span> </span><br class="NoSpacing" />Dark grey, light where fragments are small due to cracking along cleavage<span> </span><br class="NoSpacing" />Schiller (blue iridescence), characteristic of labradorite<span> </span><br class="NoSpacing" />Very fine parallel striations due to lamellar twinning</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/l112">L112 Rhyolite</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/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><span> </span><br /><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 class="NoSpacing"><span>Plagioclase feldspar forms a continuous solid solution between the sodic endmember (albite, or Ab) and the calcic endmember (anorthite, or An). The series is sub-divided into albite (An_0-10), oligoclase (An_10-30) andesine (An_30-50), labradorite (An_50-70), bytownite (An_70-90) and anorthite (An_90-100).</span></p> </div> </div> <div class="element"> <h3>Mineral Name</h3> <div class="element-text">plagioclase<br />feldspar</div> </div> felsic igneous mafic metamorphic sedimentary 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 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/be33d89fe6d9036ae8352a6f3f9a84ad.jpg c11d5dd9223d779156b594135bba0756 https://wserv3.esc.cam.ac.uk/p1acollections/files/original/6674f7f49c2139327e03ef9b7487f568.jpg 434535ac740cdd1dd8093026a4e67be7 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>Amphibole (hornblende)</h2> Description An account of the resource <div class="element"> <h3>Formula</h3> <div class="element-text"> <p>(Na,K)_0-1Ca₂(Mg,Fe²⁺,Fe³⁺,Al)₅Si_6-7.5Al_2-0.5O₂₂(OH)₂</p> </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 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> black</span><span> </span><br class="NoSpacing" /><em><span>Cleavage:</span></em><span> two at ~56°</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> pale green, green, light yellow-brown to brown</span><span> </span><br class="NoSpacing" /><em><span>Pleochroism:</span></em><span> yes</span><span> </span><br class="NoSpacing" /><em><span>Relief:</span></em><span> moderate</span><span> </span><br class="NoSpacing" /><em><span>Birefringence:</span></em><span> ~0.02; 2^nd order purple</span><span> </span><br class="NoSpacing" /><em><span>Extinction:</span></em><span> inclined</span><span> </span><br class="NoSpacing" /><em><span>Twinning:</span></em><span> simple, lamellar, common</span></p> </div> </div> <div class="element"> <h3>Mineral Specimens</h3> <div class="element-text"> <p><strong><span>M210 </span></strong><strong><span>Amphibole, hornblende</span></strong><span> </span><br /><strong>Bilen, Bohemia</strong><span> </span><br />Single, black prismatic<strong><span> </span></strong>crystal.<span> </span><br />At the ends of the crystal two sets of cleavage planes are visible, intersecting at ~56°</p> <p><strong><span>M211 </span></strong><strong><span>Amphibolite</span></strong><span> </span><br /><strong>Isle of Coll, Inner Hebrides</strong><span> </span><br />A metamorphic rock consisting almost entirely of crystals of the amphibole hornblende<span> </span><br />Black<span> </span><br />Brilliant lustre<span> </span><br />Two sets of cleavage planes intersect at ~56°</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><span> </span><br /><a href="/p1acollections/exhibits/show/igneous-rocks/l120">L120 Granodiorite</a></p> </div> </div> <div class="element"> <h3>Advanced Notes</h3> <div class="element-text"> <p class="NoSpacing"><span>The amphibole group encompasses a wide range of compositions. Even the hornblendes, which are a sub-group of the amphiboles, encompass a range of compositions (see mineral formula, above). The properties above refer to hornblende.</span></p> </div> </div> <div class="element"> <h3>Mineral Name</h3> <div class="element-text">amphibole<br />hornblende</div> </div> igneous metabasite