Minerals: Building blocks of rocks

What are minerals and how are they different from rocks? Introduction What are minerals and how are they different from rocks? What are some of the physical and chemical properties of minerals? What is the most abundant mineral group? What do all minerals in this group have in common? What are some important nonsilicate minerals? When is the term ore used with reference to a mineral? Minerals: Building blocks of rocks

rock – an aggregate of minerals Introduction Definitions Minerals versus rocks rock – an aggregate of minerals aggregate – minerals occur together as a mixture each mineral retains its distinctive properties mineral – a naturally occurring inorganic solid that possesses a definite chemical structure, which gives it a unique set of physical properties Minerals: Building blocks of rocks

Minerals exhibit the following characteristics: naturally occuring Introduction Definitions Minerals exhibit the following characteristics: naturally occuring inorganic solid definite chemical structure unique set of physical properties Minerals: Building blocks of rocks

Major properties of minerals: crystal form luster color streak Introduction Properties of minerals Major properties of minerals: crystal form luster color streak hardness cleavage fracture specific gravity Minerals: Building blocks of rocks

external arrangement of the orderly internal arrangement of atoms Introduction Properties of minerals Crystal form external arrangement of the orderly internal arrangement of atoms Minerals: Building blocks of rocks

Crystallization occurs when the KE of individual molecules decreases. Introduction Properties of minerals Crystal form – clearly evident only when the mineral forms without space restrictions Crystallization occurs when the KE of individual molecules decreases. Crystals form as they overcome solvation forces Most minerals form under intense competition for space A supersaturated solution readily forms crystals Minerals: Building blocks of rocks

Introduction Properties of minerals Minerals: Building blocks of rocks

appearance or quality of light reflected from the surface Introduction Properties of minerals Luster appearance or quality of light reflected from the surface Minerals: Building blocks of rocks

Luster metallic luster submetallic luster nonmetallic luster vitreous Introduction Properties of minerals Luster metallic luster submetallic luster nonmetallic luster vitreous pearly silky resinous earthy Minerals: Building blocks of rocks

Wavelength of visible light bouncing off a surface Introduction Properties of minerals Color Wavelength of visible light bouncing off a surface Very unreliable diagnostic property due to impurities Minerals: Building blocks of rocks

color of mineral powder streak plate more reliable than color Introduction Properties of minerals Streak color of mineral powder streak plate more reliable than color metallic (dense, dark streak) vs. nonmetallic Minerals: Building blocks of rocks

Introduction Properties of minerals Minerals: Building blocks of rocks

resistance of a mineral to abrasion or scratching use the Mohs scale Introduction Properties of minerals Hardness resistance of a mineral to abrasion or scratching use the Mohs scale Minerals: Building blocks of rocks

not all minerals have definite planes of cleavage Introduction Properties of minerals Cleavage tendency of a mineral to break along planes of weak bonding when stressed cleavage is described by the number of planes formed and the angles in which these planes meet not all minerals have definite planes of cleavage Minerals: Building blocks of rocks

Some examples of cleavage Introduction Properties of minerals Some examples of cleavage Minerals: Building blocks of rocks

minerals that do not exhibit cleavage tend to fracture when broken Introduction Properties of minerals Fracture minerals that do not exhibit cleavage tend to fracture when broken conchoidal fracture – produces smooth curved surfaces other types of fracture (splinters or fibers) most minerals fracture irregularly Minerals: Building blocks of rocks

Some examples of fracture Introduction Properties of minerals Some examples of fracture Fibrous fracture – note formation of parallel fibers Conchoidal fracture – note smooth curved surfaces Minerals: Building blocks of rocks

Introduction Properties of minerals Specific gravity compares the weight of a mineral to the weight of an equivalent volume of water Minerals: Building blocks of rocks

made of oxygen and silicon Introduction Mineral groups Mineral groups Silicates most common made of oxygen and silicon silicon-oxygen tetrahedron is the fundamental building block Minerals: Building blocks of rocks

Variants of the silicate structure Introduction Mineral groups Variants of the silicate structure addition of metals to stabilize structure (Fe, Mg, K, Na, Al, and Ca) sharing of oxygen atoms results to a variety of configurations single chains double chains sheets Minerals: Building blocks of rocks

Introduction Mineral groups Minerals: Building blocks of rocks

Variants of the silicate structure Introduction Mineral groups Variants of the silicate structure the ratio of oxygen to silicon atoms varies among the different silicate structures high or low silicon content based on this ratio important in the formation of igneous rocks families of minerals same structure but with varying amounts of metals olivine, (Mg,Fe)2SiO4 Minerals: Building blocks of rocks

Dark silicate minerals ferromagnesian silicates Introduction Mineral groups Dark silicate minerals ferromagnesian silicates contains iron and/or magnesium dark color and greater specific gravity Minerals: Building blocks of rocks

olivine hornblende biotite Introduction Mineral groups Minerals: Building blocks of rocks

Light silicate minerals nonferromagnesian silicates Introduction Mineral groups Light silicate minerals nonferromagnesian silicates contains Al, K, Ca, and/or Na light color and smaller specific gravity Minerals: Building blocks of rocks

Light silicate minerals Introduction Mineral groups Light silicate minerals feldspars – most common light silicates (most common mineral on Earth) orthoclase feldspar – has K ions plagioclase feldspar – has Na and Ca light color and smaller specific gravity quartz – consists entirely of silicon and oxygen Minerals: Building blocks of rocks

plagioclase feldspar rose quartz orthoclase feldspar Introduction Mineral groups plagioclase feldspar rose quartz orthoclase feldspar Minerals: Building blocks of rocks

carbonate minerals (limestone) halite (table salt) Introduction Mineral groups Nonsilicate minerals carbonate minerals (limestone) halite (table salt) gypsum (used in plaster, building materials) metal ores (Fe, Zn, Pb) native elements – free occurring, not in compounds (Au, Ag, C) Minerals: Building blocks of rocks

limestone Introduction Mineral groups Minerals: Building blocks of rocks

pink halite gypsum Introduction Mineral groups Minerals: Building blocks of rocks

malachite Introduction Mineral groups Minerals: Building blocks of rocks

Introduction Mineral groups Minerals: Building blocks of rocks

Introduction Mineral groups Minerals: Building blocks of rocks

References Minerals: Building blocks of rocks http://cmsc.minotstateu.edu/Labs/web%20minerals/Streak.html http://en.wikipedia.org/wiki/Pyrite http://www.canadianrockhound.ca/2002/01/cr0206102_monte_bianco.html http://itl.chem.ufl.edu/2041_f00/lectures/lec_i.html http://www.diamondjewelersonline.com/ http://www.essencesonline.com/Alaskan-gem.htm http://www.gc.maricopa.edu/earthsci/imagearchive/quartz.htm http://www.geology.sfasu.edu/sld002.html http://www.gfy.ku.dk/~flyvholm/Ice_crystals_02_07_04.htm Minerals: Building blocks of rocks

References Minerals: Building blocks of rocks http://www.its.caltech.edu/~atomic/snowcrystals/primer/primer.htm http://www.iun.edu/~geos/Zoran%20IUN/G%20101/Lecture%20Outlines/Minerals.htm http://lpc1.clpccd.cc.ca.us/lpc/hanna/examspractice/geo10lab/mineralphotos/mineralphotosC.htm http://www.mandarava.com/Retail/Crystal_shop.htm http://www.marinmineral.com/africa5.html http://www.minresco.com/display/disp02.htm http://www.pitt.edu/~cejones/GeoImages/1Minerals/2SedimentaryMineralz/Calcite_Dolomite.html http://www.rocksandminerals.com/hardness/mohs.htm http://www.soes.soton.ac.uk/resources/collection/minerals/minerals/pages/M30-Talc.htm http://www.usoe.k12.ut.us/curr/science/sciber00/7th/earth/sciber/minerid.htm Minerals: Building blocks of rocks