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3/25/2015 Learning goals 1.Understand the definition of mineral 2.Distinguish differences between mineral and non mineral substances 3.Understand different types of silicate minerals De finitio n & 4.Learn about Nesosilicates, particularly

  1. 3/25/2015 Learning goals 1.Understand the definition of mineral 2.Distinguish differences between mineral and non ‐ mineral substances 3.Understand different types of silicate minerals De finitio n & 4.Learn about Nesosilicates, particularly olivine and garnet, and remember their physical T ype s o f Mine ra l characteristics W. K a nitpa nya c ha ro e n mag e so urc e : http://www.c ario nmine raux.c o m/mine raux/Mine raux_Juille t_ao ut_2008/q uartz_ve rt_c hine _1.jpg I 1. I no rg a nic • Mineral is a naturally occurring substance that is De finitio n so lid solid and inorganic representable by a chemical formula, and has an ordered atomic structure. It is different from a rock, which can be an aggregate 2. Na tura lly of minerals or non ‐ minerals and does not have a f i l i l d d t h o c c urring i specific chemical composition. 3. De finite c he mic a l c o mpo sitio n 4. Orde re d a to mic a rra ng e me nt mag e so urc e : http://www.c ario nmine raux.c o m/mine raux/Mine raux_Juille t_ao ut_2008/q uartz_ve rt_c hine _1.jpg I 1

  2. 3/25/2015 I s sa lt a mine ra l ? • Salt also known as sodium chloride or halite is an ionic compound with the chemical formula NaCl. This mineral can be easily found in our daily lives such as in food, preservatives, and industrial processes. Ye s: Ha lite (Na Cl) I mag e so urc e : http://www.te atro naturale .it/me dia/img /c ib o /2014/S alt-014.jpg • In solid sodium chloride , each ion is surrounded by six ions of the opposite charge as expected on electrostatic grounds. The surrounding ions are located at the vertices of a regular octahedron. The larger Cl ions (green) are arranged in a cubic array g (g ) g y whereas the smaller Na ions (yellow) fill all the cubic gaps (octahedral voids) between them. This same basic structure is found in many other minerals and is commonly known as the rock ‐ salt crystal structure. • It can be represented as a face ‐ centered cubic (fcc) lattice with a two ‐ atom basis or as two interpenetrating face centered cubic lattices. The first atom is located at each lattice point, and the second atom is located half way between lattice points along the fcc unit cell edge. F a c e -Ce nte re d Cub ic (F CC) I mag e so urc e : https://pe da.ne t/o ppimate riaalit/e -o ppi/lukio /n%C3%A4yte luvut/e ke 2/41/ke rtaus/4-2-io nisido s/nac l- kide rake nne :file /do wnlo ad/8b b e e b 2c 420e 44e b 40b b d450b a4b 80f2e 45d0347/nac l-kide rake nne .jpg 2

  3. 3/25/2015 I s sno wfla ke a mine ra l ? • A snowflake starts forming when a tiny dust or pollen particle comes into contact with water vapor high in Earth's atmosphere. The water vapor coats the tiny particle and freezes into a tiny crystal of ice. This tiny crystal will be the "seed" from which a Thi ti t l ill b th " d" f hi h snowflake will grow. Snowflake is thus mineral because it is naturally occurring solid with a definite chemical composition and an ordered internal structure. • However an ice cube made in a refrigerator would However an ice cube made in a refrigerator would not be considered a mineral because it was produced by the actions of people. Ye s: H 2 O I mag e so urc e : http://www.wallpape rsdb .o rg /wallpape rs/ho lidays/sno wflake _c lo se _1920x1200.jpg mag e so urc e : http://wallpape rswide .c o m/sno wflake -wallpape rs.html I • Snowflakes always have 6 sides because when water molecules freeze they form a 6 ‐ sided ring (hexagon). As more molecules freeze, the snowflake becomes a L iq uid H 2 O 6 ‐ pointed crystal. The newly ‐ formed ice crystal (snowflake) is heavier than the surrounding air and it ( fl k ) i h i th th di i d it fre e ze begins falling. • As it falls towards Earth through humid air more water vapor freezes onto the surface of the tiny crystal. The snowflake grows larger and larger as it falls enlarging the hexagonal pattern falls, enlarging the hexagonal pattern. g ro w Na tura lly o c c urre d So lid H 2 O I mag e so urc e : http://www.e astte nne sse e wildflo we rs.c o m/imag e s/S no wflake _mo le c ule s.jpg 3

  4. 3/25/2015 • Although all snowflakes have a hexagonal shape other details of their geometry can vary. These variations are produced by different temperature and humidity conditions through which the snowflake falls. fl k f ll • Some temperature/humidity combinations produce flakes with long needle ‐ like arms. Other conditions produce flakes with wide flat arms. Other conditions produce thin, branching arms. Just like o the r mine ra ls, sno wfla ke s ha ve ma ny struc ture s! I mag e so urc e : http://www.e arthzine .o rg /wp-c o nte nt/uplo ads/2012/07/I mag e -o f-diffe re nt-type s-o f-sno w-flake s.jpg I s sug a r a mine ra l ? • Sugar can form crystals, but since sugar is composed of organic material , these crystals are not minerals. Minerals have to be naturally created or else they are classified as man ‐ made substances. No : C 12 H 22 O 11 I mag e so urc e : http://www.o asisdisc ussio ns.c a/wp-c o nte nt/uplo ads/2014/03/b ig sto c k-S e ve ral-type s-o f-white -sug ar-41900299.jpg 4.jp g 4

  5. 3/25/2015 • Sugar forms crystal but it’s organic ! Sug a r fo rms c rysta l b ut it’ s or ganic ! I mag e so urc e : http://s.hswstatic .c o m/g if/fo o d-g luc o se .g if How many mine ra ls a re o ut the re ? • There are approximately 3800 known minerals. About 30 to 50 new minerals are described and one a . 400 or two minerals are discredited each year. The most b . 4,000 complete listing of minerals is J. Mandarino Fleischer's Glossary of Mineral Species 1999 Fl i h ' Gl f Mi l S i 1999 c . 40,000 40 000 published by the Mineralogical Record. d. 400,000 I mag e so urc e http://me dia.ido wnlo adblo g .c o m/wp-c o nte nt/uplo ads/2014/06/Yo se mite .jpg 5

  6. 3/25/2015 T ype • Crystalline solids have regular ordered 3D arrays of b ase d o n atomic ar components held together by uniform r ange me nt intermolecular forces, whereas the components of Amorphous solids are not arranged in regular arrays. (from the Greek ámorphos, meaning (f th G k á h i “shapeless”). Crysta lline Amo rpho us e .g . q ua rtz (SiO 2 ) e .g . g la ss, o pa l (SiO 2 ) I mag e so urc e : http://uplo ad.wikime dia.o rg /wikipe dia/c o mmo ns/thumb /0/05/Crystalline _po lyc rystalline _amo rpho us2.svg /2000px-Crysta lline _po lyc rystalline _amo rpho us2.svg .png T ype • Minerals can be categorized into 2 groups based on their chemical composition. b ase d o n c he mic al c omposition • 1. Silicate minerals The most common mineral group on Earth is the silicate minerals, which all have the elements silica and oxygen as their main ingredients. Most silicates form when molten rock cools, either at or near the Earth's surface or deep underground e.g. Orthoclase • 2. Non ‐ silicate minerals 2 N ili t i l Some of non ‐ silicates form when magma cools, while Silic a te s No n-silic a te s others form when water evaporates away leaving Must c o nta in Si a nd O mineral crystals behind e.g. Calcite , or when other e .g . Ca lc ite (Ca CO 3 ) e .g . Ortho c a lse (K AlSi 3 O 8 ) minerals decompose. mag e so urc e http://www.kidzro c ks.c o m/v/vspfile s/pho to s/kidzkit-Calc ite -Rho mb -2.jpg ; http://www.g e msto ne b uzz.c o m/file s/g e msto ne / I fe ldspar.jpg 6

  7. 3/25/2015 T he Six Silic a te s • The basic chemical unit of silicates is the (SiO4) tetrahedron shaped anionic group with a negative four charge ( ‐ 4). They can form as single units, double units, chains, sheets, rings and framework structures. t t (SiO 4 ) 4- Side vie w T e tra he dro n Silic o n Silic o n Oxyg e n T o p vie w I mag e so urc e http://www.thiso lde arth.ne t/I mag e s/silic ate _struc ture s.jpg T he Six Silic a te s • The Silicates are divided into 6 groups, not by their Si : O chemistries, but by their structures : Ne so silic a te s Isla nd 1: 4 • 1. Nesosilicates (single tetrahedrons) Sing le te trahe dro n o r Ortho silic a te s • 2. Sorosilicates (double tetrahedrons) 2 : 7 2 : 7 Bo w tie Bo w tie Sor o silic a te s Do ub le te trahe dro n • 3. Inosilicates (single and double chains) • 4. Cyclosilicates (rings) 1 : 3 Cyc lo silic a te s Ring • 5. Phyllosilicates (sheets) • 6. Tectosilicates (frameworks) Ino silic a te s 4 : 11 Cha in Sing le o r Do ub le g Phyllo silic a te s 2 : 5 She e t e c to silic a te s T 1 : 2 F ra me wo rk I mag e so urc e http://www.thiso lde arth.ne t/I mag e s/silic ate _struc ture s.jpg 7

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