{"id":109,"date":"2015-07-10T22:37:07","date_gmt":"2015-07-10T22:37:07","guid":{"rendered":"https:\/\/courses.candelalearning.com\/earthscienceck12\/?post_type=chapter&#038;p=109"},"modified":"2015-07-31T22:04:28","modified_gmt":"2015-07-31T22:04:28","slug":"mineral-identification","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/earthscienceck12\/chapter\/mineral-identification\/","title":{"raw":"Mineral Identification","rendered":"Mineral Identification"},"content":{"raw":"&nbsp;\r\n<h2>Lesson Objectives<\/h2>\r\n<ul>\r\n\t<li>Explain how minerals are identified.<\/li>\r\n\t<li>Describe how color, luster, and streak are used to identify minerals.<\/li>\r\n\t<li>Summarize specific gravity.<\/li>\r\n\t<li>Explain how the hardness of a mineral is measured.<\/li>\r\n\t<li>Describe the properties of cleavage and fracture.<\/li>\r\n\t<li>Identify additional properties that can be used to identify some minerals.<\/li>\r\n<\/ul>\r\n<h2>Vocabulary<\/h2>\r\n<ul>\r\n\t<li>cleavage<\/li>\r\n\t<li>density<\/li>\r\n\t<li>fracture<\/li>\r\n\t<li>hardness<\/li>\r\n\t<li>luster<\/li>\r\n\t<li>mineralogist<\/li>\r\n\t<li>streak<\/li>\r\n<\/ul>\r\n<h2>Introduction<\/h2>\r\nMinerals can be identified by their physical characteristics. The physical properties of minerals are related to their chemical composition and bonding. Some characteristics, such as a mineral's hardness, are more useful for mineral identification. Color is readily observable and certainly obvious, but it is usually less reliable than other physical properties.\r\n<h2>How are Minerals Identified?<\/h2>\r\n<strong>Mineralogists<\/strong> are scientists who study minerals. One of the things mineralogists must do is identify and categorize minerals. While a mineralogist might use a high-powered microscope to identify some minerals, most are recognizable using physical properties.\r\n\r\nCheck out the mineral in <strong>Figure<\/strong> <a href=\"#x-ck12-SFMtMDMtMDMtMTctUHlyaXRl\">below<\/a>. What is the mineral\u2019s color? What is its shape? Are the individual crystals shiny or dull? Are there lines (striations) running across the minerals? In this lesson, the properties used to identify minerals are described in more detail.\r\n<div class=\"x-ck12-img-postcard x-ck12-nofloat\"><!-- @@author=\"Flickr:pnjunction2007\" --><!-- @@url=\"http:\/\/flickr.com\/photos\/8390413@N03\/533216371\/\" --><!-- @@license=\"CC BY 2.0\" --><img id=\"x-ck12-SFMtMDMtMDMtMTctUHlyaXRl\" title=\"\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/682\/2015\/07\/22223112\/201412291419878202719844_9388297cfc28d73f8b738f8f4d295831-201412291419879636088732.jpg\" alt=\"\" longdesc=\"This%20mineral%20has%20shiny%2C%20gold%2C%20cubic%20crystals%20with%20striations%2C%20so%20it%20is%20pyrite.%20\" \/>This mineral has shiny, gold, cubic crystals with striations, so it is pyrite.\r\n\r\n<\/div>\r\n<h2>Color, Streak, and Luster<\/h2>\r\nDiamonds are popular gemstones because the way they reflect light makes them very sparkly. Turquoise is prized for its striking greenish-blue color. Notice that specific terms are being used to describe the appearance of minerals.\r\n<h3>Color<\/h3>\r\nColor is rarely very useful for identifying a mineral. Different minerals may be the same color. Real gold, as seen in <strong>Figure<\/strong> <a href=\"#x-ck12-SFMtRVMtMDMtMDMtMTgtR29sZA..\">below<\/a>, is very similar in color to the pyrite in <strong>Figure<\/strong> <a href=\"#x-ck12-SFMtMDMtMDMtMTctUHlyaXRl\">above<\/a>.\r\n<div class=\"x-ck12-img-postcard x-ck12-nofloat\"><!-- @@author=\"Aram Dulyan\" --><!-- @@url=\"http:\/\/commons.wikimedia.org\/wiki\/File:Native_gold_nuggets.jpg\" --><!-- @@license=\"Public Domain\" --><img id=\"x-ck12-SFMtRVMtMDMtMDMtMTgtR29sZA..\" title=\"Gold nugget\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/682\/2015\/07\/22223114\/201412291419878202762390_b9bf3347e3f12c1f7a54efaa1981da6f-201412291419879636757698.jpg\" alt=\"Gold nugget\" longdesc=\"This%20mineral%20is%20shiny%2C%20very%20soft%2C%20heavy%2C%20and%20gold%20in%20color%2C%20and%20is%20actually%20gold.%20\" \/>This mineral is shiny, very soft, heavy, and gold in color, and is actually gold.\r\n\r\n<\/div>\r\nThe same mineral may also be found in different colors. <strong>Figure<\/strong> <a href=\"#x-ck12-TVMtRVMtMDMtUXVhcnR6IGNvbXBvc2l0ZS5wbmc.\">below<\/a> shows one sample of quartz that is colorless and another quartz that is purple. A tiny amount of iron makes the quartz purple. Many minerals are colored by chemical impurities.\r\n<div class=\"x-ck12-img-postcard x-ck12-nofloat\"><!-- @@author=\"Left: Stephanie Clifford; Right: Mauro Cateb\" --><!-- @@url=\"Left: http:\/\/www.flickr.com\/photos\/30486689@N08\/2933050796\/; Right: http:\/\/www.flickr.com\/photos\/mauroescritor\/6544435963\/\" --><!-- @@license=\"CC BY 2.0\" --><img id=\"x-ck12-TVMtRVMtMDMtUXVhcnR6IGNvbXBvc2l0ZS5wbmc.\" title=\"\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/682\/2015\/07\/22223115\/201412291419878202777650_bd5b64fdcb63ee913c631dacfe378741-201412291419879637113499.jpg\" alt=\"\" longdesc=\"Purple%20quartz%2C%20known%20as%20amethyst%2C%20and%20clear%20quartz%20are%20the%20same%20mineral%20despite%20the%20different%20colors.%20\" \/>Purple quartz, known as amethyst, and clear quartz are the same mineral despite the different colors.\r\n\r\n<\/div>\r\n<h3>Streak<\/h3>\r\n<strong>Streak<\/strong> is the color of a mineral\u2019s powder. Streak is a more reliable property than color because streak does not vary. Minerals that are the same color may have a different colored streak. Many minerals, such as the quartz in the <strong>Figure<\/strong> <a href=\"#x-ck12-TVMtRVMtMDMtUXVhcnR6IGNvbXBvc2l0ZS5wbmc.\">above<\/a>, do not have streak.\r\n\r\nTo check streak, scrape the mineral across an unglazed porcelain plate (<strong>Figure<\/strong> <a href=\"#x-ck12-SFMtRVMtMDMtMDMtMjAtU3RyZWFraW5nLWhlbWF0aXRl\">below<\/a>). Yellow-gold pyrite has a blackish streak, another indicator that pyrite is not gold, which has a golden yellow streak.\r\n<div class=\"x-ck12-img-postcard x-ck12-nofloat\"><!-- @@author=\"CK-12 Foundation\" --><!-- @@url=\"CK-12 Foundation\" --><!-- @@license=\"CC BY-NC 3.0\" --><img id=\"x-ck12-SFMtRVMtMDMtMDMtMjAtU3RyZWFraW5nLWhlbWF0aXRl\" title=\"\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/682\/2015\/07\/22223116\/201412291419878202792910_856678cdab5a2d4e49c6292a9a950476-201412291419879638252191.jpg\" alt=\"\" longdesc=\"The%20streak%20of%20hematite%20across%20an%20unglazed%20porcelain%20plate%20is%20red-brown.%20\" \/>The streak of hematite across an unglazed porcelain plate is red-brown.\r\n\r\n<\/div>\r\n<h3>Luster<\/h3>\r\n<strong>Luster<\/strong> describes the reflection of light off a mineral\u2019s surface. Mineralogists have special terms to describe luster. One simple way to classify luster is based on whether the mineral is metallic or non-metallic. Minerals that are opaque and shiny, such as pyrite, have a metallic luster. Minerals such as quartz have a non-metallic luster. Different types of non-metallic luster are described in <strong>Table<\/strong> <a href=\"#x-ck12-dGFibGU6bHVzdGVy\">below<\/a>.\r\n<table id=\"x-ck12-dGFibGU6bHVzdGVy\" title=\"Six types of non-metallic luster\" border=\"1\" summary=\"Six types of non-metallic luster\"><caption>Six types of non-metallic luster.<\/caption>\r\n<thead>\r\n<tr>\r\n<th><strong>Luster<\/strong><\/th>\r\n<th><strong>Appearance<\/strong><\/th>\r\n<\/tr>\r\n<\/thead>\r\n<tbody>\r\n<tr>\r\n<td>Adamantine<\/td>\r\n<td>Sparkly<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>Earthy<\/td>\r\n<td>Dull, clay-like<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>Pearly<\/td>\r\n<td>Pearl-like<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>Resinous<\/td>\r\n<td>Like resins, such as tree sap<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>Silky<\/td>\r\n<td>Soft-looking with long fibers<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>Vitreous<\/td>\r\n<td>Glassy<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\nCan you match the minerals in <strong>Figure<\/strong> <a href=\"#x-ck12-SFMtRVMtMDMtMDMtMjEtRGlhbW9uZC1xdWFydHotc3VsZnVy\">below<\/a> with the correct luster from <strong>Table<\/strong> <a href=\"#x-ck12-dGFibGU6bHVzdGVy\">above<\/a>?\r\n<div class=\"x-ck12-img-fullpage x-ck12-nofloat\"><!-- @@author=\"(a) Flickr:Glass and Mirror; (b) Courtesy of the US Geological Survey; (c) Courtesy of Smithsonian Institution\" --><!-- @@url=\"(a) http:\/\/www.flickr.com\/photos\/hokaicila\/1543565434\/; (b) http:\/\/commons.wikimedia.org\/wiki\/File:Quartz_Crystal.jpg; (c) http:\/\/commons.wikimedia.org\/wiki\/File:Sulfur.jpg\" --><!-- @@license=\"(a) CC BY 2.0, (b) Public Domain; (c) Public Domain\" --><img id=\"x-ck12-SFMtRVMtMDMtMDMtMjEtRGlhbW9uZC1xdWFydHotc3VsZnVy\" title=\"\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/682\/2015\/07\/22223118\/201412291419878202812429_9c45a8fcfdd91cecb7eb9d79743fedd2-201412291419879638691972.jpg\" alt=\"\" longdesc=\"%28a%29%20Diamond%20has%20an%20adamantine%20luster.%20%28b%29%20Quartz%20is%20not%20sparkly%20and%20has%20a%20vitreous%2C%20or%20glassy%2C%20luster.%20%28b%29%20Sulfur%20reflects%20less%20light%20than%20quartz%2C%20so%20it%20has%20a%20resinous%20luster.%20\" \/>(a) Diamond has an adamantine luster. (b) Quartz is not sparkly and has a vitreous, or glassy, luster. (b) Sulfur reflects less light than quartz, so it has a resinous luster.\r\n\r\n<\/div>\r\n<h2>Specific Gravity<\/h2>\r\n<strong>Density<\/strong> describes how much matter is in a certain amount of space: density = mass\/volume.\r\n\r\nMass is a measure of the amount of matter in an object. The amount of space an object takes up is described by its volume. The density of an object depends on its mass and its volume. For example, the water in a drinking glass has the same density as the water in the same volume of a swimming pool.\r\n\r\nGold has a density of about 19 g\/cm<sup>3<\/sup>; pyrite has a density of about 5 g\/cm<sup>3<\/sup> - that\u2019s another way to tell pyrite from gold. Quartz is even less dense than pyrite and has a density of 2.7 g\/cm<sup>3<\/sup>.\r\n\r\nThe specific gravity of a substance compares its density to that of water. Substances that are more dense have higher specific gravity.\r\n<h2>Hardness<\/h2>\r\n<strong>Hardness<\/strong> is a measure of whether a mineral will scratch or be scratched. Mohs Hardness Scale, shown in <strong>Table<\/strong> <a href=\"#x-ck12-dGFibGU6aGFyZG5lc3M.\">below<\/a>, is a reference for mineral hardness.\r\n<table id=\"x-ck12-dGFibGU6aGFyZG5lc3M.\" title=\"Mohs Hardness Scale: 1 (softest) to 10 (hardest)\" border=\"1\" summary=\"Mohs Hardness Scale: 1 (softest) to 10 (hardest)\"><caption>Mohs Hardness Scale: 1 (softest) to 10 (hardest).<\/caption>\r\n<thead>\r\n<tr>\r\n<th><strong>Hardness<\/strong><\/th>\r\n<th><strong>Mineral<\/strong><\/th>\r\n<\/tr>\r\n<\/thead>\r\n<tbody>\r\n<tr>\r\n<td>1<\/td>\r\n<td>Talc<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>2<\/td>\r\n<td>Gypsum<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>3<\/td>\r\n<td>Calcite<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>4<\/td>\r\n<td>Fluorite<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>5<\/td>\r\n<td>Apatite<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>6<\/td>\r\n<td>Feldspar<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>7<\/td>\r\n<td>Quartz<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>8<\/td>\r\n<td>Topaz<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>9<\/td>\r\n<td>Corundum<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>10<\/td>\r\n<td>Diamond<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\nWith a Mohs scale, anyone can test an unknown mineral for its hardness. Imagine you have an unknown mineral. You find that it can scratch fluorite or even apatite, but feldspar scratches it. You know then that the mineral\u2019s hardness is between 5 and 6. Note that no other mineral can scratch diamond.\r\n<h2>Cleavage and Fracture<\/h2>\r\nBreaking a mineral breaks its chemical bonds. Since some bonds are weaker than other bonds, each type of mineral is likely to break where the bonds between the atoms are weaker. For that reason, minerals break apart in characteristic ways.\r\n\r\n<strong>Cleavage<\/strong> is the tendency of a mineral to break along certain planes to make smooth surfaces. Halite breaks between layers of sodium and chlorine to form cubes with smooth surfaces (<strong>Figure<\/strong> <a href=\"#x-ck12-SFMtRVMtMDMtMDMtMjItU29kaXVtLWNobG9yaWRlLXdhdGVyLXNwYWNl\">below<\/a>).\r\n<div class=\"x-ck12-img-thumbnail x-ck12-nofloat\"><!-- @@author=\"Courtesy of NASA\" --><!-- @@url=\"http:\/\/www.nasa.gov\/multimedia\/imagegallery\/image_feature_1561.html\" --><!-- @@license=\"Public Domain\" --><img id=\"x-ck12-SFMtRVMtMDMtMDMtMjItU29kaXVtLWNobG9yaWRlLXdhdGVyLXNwYWNl\" title=\"\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/682\/2015\/07\/22223119\/201412291419878202835973_695cf6ad3bef2a183d1036b53cabb4ab-201412291419879639152658.jpg\" alt=\"\" longdesc=\"A%20close-up%20view%20of%20sodium%20chloride%20in%20a%20water%20bubble%20aboard%20the%20International%20Space%20Station.%20\" \/>A close-up view of sodium chloride in a water bubble aboard the International Space Station.\r\n\r\n<\/div>\r\nMica has cleavage in one direction and forms sheets (<strong>Figure<\/strong> <a href=\"#x-ck12-SFMtRVMtMDMtMDMtMjMtTWljYS1zaGVldA..\">below<\/a>).\r\n<div class=\"x-ck12-img-postcard x-ck12-nofloat\"><!-- @@author=\"User:\u0e19\u0e31\u0e19\u0e17\u0e20\u0e23\u0e13\u0e4c \u0e19\u0e34\u0e22\u0e21\u0e1a\u0e27\u0e23\u0e27\u0e31\u0e12\u0e19\u0e4c\/Wikimedia Commons\" --><!-- @@url=\"http:\/\/commons.wikimedia.org\/wiki\/File:Nanta-aom1.jpg\" --><!-- @@license=\"Public Domain\" --><img id=\"x-ck12-SFMtRVMtMDMtMDMtMjMtTWljYS1zaGVldA..\" title=\"\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/682\/2015\/07\/22223120\/201412291419878202915236_2ae989336045c4b365a1a4d5bea260f2-201412291419879639839674.jpg\" alt=\"\" longdesc=\"Sheets%20of%20mica.%20\" \/>Sheets of mica.\r\n\r\n<\/div>\r\nMinerals can cleave into polygons. Fluorite forms octahedrons (<strong>Figure<\/strong> <a href=\"#x-ck12-SFMtRVMtMDMtMjQtRmx1b3JpdGUtb2N0YWhlZHJhbC1jbGVhdmFnZQ..\">below<\/a>).\r\n<div class=\"x-ck12-img-thumbnail x-ck12-nofloat\"><!-- @@author=\"\" --><!-- @@url=\"http:\/\/commons.wikimedia.org\/wiki\/File:Rough_diamond_-_hardest_known_mineral.jpg\" --><!-- @@license=\"Public Domain\" --><img id=\"x-ck12-SFMtRVMtMDMtMjQtRmx1b3JpdGUtb2N0YWhlZHJhbC1jbGVhdmFnZQ..\" title=\"\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/682\/2015\/07\/22223122\/201412291419878202930202_b1344dae2cb72feb80d266f3474f834b-201412291419879640439931.jpg\" alt=\"\" longdesc=\"This%20rough%20diamond%20shows%20its%20octahedral%20cleavage.%20\" \/>This rough diamond shows its octahedral cleavage.\r\n\r\n<\/div>\r\nOne reason gemstones are beautiful is that the cleavage planes make an attractive crystal shape with smooth faces.\r\n\r\n<strong>Fracture<\/strong> is a break in a mineral that is not along a cleavage plane. Fracture is not always the same in the same mineral because fracture is not determined by the structure of the mineral.\r\n\r\nMinerals may have characteristic fractures (<strong>Figure<\/strong> <a href=\"#x-ck12-SFMtRVMtMDMtMDMtMjUtQ2hyeXNvdGlsZS1zcGxpbnRlcnk.\">below<\/a>). Metals usually fracture into jagged edges. If a mineral splinters like wood, it may be fibrous. Some minerals, such as quartz, form smooth curved surfaces when they fracture.\r\n<div class=\"x-ck12-img-postcard x-ck12-nofloat\"><!-- @@author=\"Courtesy of Andrew Silver, USGS\" --><!-- @@url=\"http:\/\/commons.wikimedia.org\/wiki\/File:Chrysotile_-_USGS_Mineral_Specimens_302.jpg\" --><!-- @@license=\"Public Domain\" --><img id=\"x-ck12-SFMtRVMtMDMtMDMtMjUtQ2hyeXNvdGlsZS1zcGxpbnRlcnk.\" title=\"\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/682\/2015\/07\/22223123\/201412291419878202946102_984fbcdf364b4520f8da6f2e7cc98c91-201412291419879640928735.jpg\" alt=\"\" longdesc=\"Chrysotile%20has%20splintery%20fracture.%20\" \/>Chrysotile has splintery fracture.\r\n\r\n<\/div>\r\n<h2>Other Identifying Characteristics<\/h2>\r\nSome minerals have other unique properties, some of which are listed in <strong>Table<\/strong> <a href=\"#x-ck12-dGFibGU6aWRlbnRpZmllcnM.\">below<\/a>. Can you name a unique property that would allow you to instantly identify a mineral that\u2019s been described quite a bit in this chapter? (Hint: It is most likely found on your dinner table.)\r\n<table id=\"x-ck12-dGFibGU6aWRlbnRpZmllcnM.\" title=\"Unique Identifying Mineral Properties\" border=\"1\" summary=\"Unique Identifying Mineral Properties\"><caption>Some minerals have unusual properties that can be used for identification.<\/caption>\r\n<thead>\r\n<tr>\r\n<th><strong>Property<\/strong><\/th>\r\n<th><strong>Description<\/strong><\/th>\r\n<th><strong>Example of Mineral<\/strong><\/th>\r\n<\/tr>\r\n<\/thead>\r\n<tbody>\r\n<tr>\r\n<td>Fluorescence<\/td>\r\n<td>Mineral glows under ultraviolet light<\/td>\r\n<td>Fluorite<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>Magnetism<\/td>\r\n<td>Mineral is attracted to a magnet<\/td>\r\n<td>Magnetite<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>Radioactivity<\/td>\r\n<td>Mineral gives off radiation that can be measured with Geiger counter<\/td>\r\n<td>Uraninite<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>Reactivity<\/td>\r\n<td>Bubbles form when mineral is exposed to a weak acid<\/td>\r\n<td>Calcite<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>Smell<\/td>\r\n<td>Some minerals have a distinctive smell<\/td>\r\n<td>Sulfur (smells like rotten eggs)<\/td>\r\n<\/tr>\r\n<tr>\r\n<td>Taste<\/td>\r\n<td>Some minerals taste salty<\/td>\r\n<td>Halite<\/td>\r\n<\/tr>\r\n<\/tbody>\r\n<\/table>\r\nA simple lesson on how to identify minerals is seen in this video.\r\n<h2>Lesson Summary<\/h2>\r\n<ul>\r\n\t<li>Minerals have distinctive properties that can be used to help identify them.<\/li>\r\n\t<li>Color and luster describe the mineral\u2019s outer appearance. Streak is the color of the powder.<\/li>\r\n\t<li>A mineral has a characteristic density.<\/li>\r\n\t<li>Mohs Hardness Scale is used to compare the hardness of minerals.<\/li>\r\n\t<li>Cleavage or the characteristic way a mineral breaks depends on the crystal structure of the mineral.<\/li>\r\n\t<li>Some minerals have special properties that can be used to help identify them.<\/li>\r\n<\/ul>\r\n<h2>Review Questions<\/h2>\r\n<ol id=\"x-ck12-ODIyMDNjNjE2ZTQxMTk3NTA4ZThiMGE1ZjRlMTdmNjc.-dez\" class=\"x-ck12-decimal\">\r\n\t<li>Which properties of a mineral describe the way it breaks apart?<\/li>\r\n\t<li>A mineral looks dry and chalky. What sort of luster does it have?<\/li>\r\n\t<li>What causes a mineral to have the properties that it has?<\/li>\r\n\t<li>Apatite scratches the surface of an unknown mineral. Which mineral would you use next to test the mineral\u2019s hardness \u2014 fluorite or feldspar? Explain your reasoning.<\/li>\r\n\t<li>Why is streak more reliable than color when identifying a mineral?<\/li>\r\n\t<li>Mineral A has a density of 5 g\/cm<sup>3<\/sup>. Mineral B is twice as dense as Mineral A. What is the density of Mineral B?<\/li>\r\n\t<li>Why do some minerals cleave along certain planes?<\/li>\r\n<\/ol>\r\n<h2>Further Reading \/ Supplemental Links<\/h2>\r\n<ul>\r\n\t<li><a href=\"http:\/\/geology.csupomona.edu\/alert\/mineral\/color.htm\/\">Mineral Color<\/a><\/li>\r\n\t<li><a href=\"http:\/\/www.galleries.com\/minerals\/physical.htm\">Physical Characteristics of Minerals<\/a>.<\/li>\r\n\t<li><a href=\"http:\/\/geology.csupomona.edu\/alert\/mineral\/minerals.htm\">Mineral Identification<\/a>.<\/li>\r\n<\/ul>\r\n<h2>Points to Consider<\/h2>\r\n<ul>\r\n\t<li>If a mineral is magnetic, do you know for certain what mineral it is?<\/li>\r\n\t<li>Some minerals are colored because they contain chemical impurities. How did the impurities get into the mineral?<\/li>\r\n\t<li>What two properties of a mineral sample would you have to measure to calculate its density?<\/li>\r\n\t<li>How much do minerals reflect the environment in which they formed?<\/li>\r\n<\/ul>\r\n&nbsp;","rendered":"<p>&nbsp;<\/p>\n<h2>Lesson Objectives<\/h2>\n<ul>\n<li>Explain how minerals are identified.<\/li>\n<li>Describe how color, luster, and streak are used to identify minerals.<\/li>\n<li>Summarize specific gravity.<\/li>\n<li>Explain how the hardness of a mineral is measured.<\/li>\n<li>Describe the properties of cleavage and fracture.<\/li>\n<li>Identify additional properties that can be used to identify some minerals.<\/li>\n<\/ul>\n<h2>Vocabulary<\/h2>\n<ul>\n<li>cleavage<\/li>\n<li>density<\/li>\n<li>fracture<\/li>\n<li>hardness<\/li>\n<li>luster<\/li>\n<li>mineralogist<\/li>\n<li>streak<\/li>\n<\/ul>\n<h2>Introduction<\/h2>\n<p>Minerals can be identified by their physical characteristics. The physical properties of minerals are related to their chemical composition and bonding. Some characteristics, such as a mineral&#8217;s hardness, are more useful for mineral identification. Color is readily observable and certainly obvious, but it is usually less reliable than other physical properties.<\/p>\n<h2>How are Minerals Identified?<\/h2>\n<p><strong>Mineralogists<\/strong> are scientists who study minerals. One of the things mineralogists must do is identify and categorize minerals. While a mineralogist might use a high-powered microscope to identify some minerals, most are recognizable using physical properties.<\/p>\n<p>Check out the mineral in <strong>Figure<\/strong> <a href=\"#x-ck12-SFMtMDMtMDMtMTctUHlyaXRl\">below<\/a>. What is the mineral\u2019s color? What is its shape? Are the individual crystals shiny or dull? Are there lines (striations) running across the minerals? In this lesson, the properties used to identify minerals are described in more detail.<\/p>\n<div class=\"x-ck12-img-postcard x-ck12-nofloat\"><!-- @@author=\"Flickr:pnjunction2007\" --><!-- @@url=\"http:\/\/flickr.com\/photos\/8390413@N03\/533216371\/\" --><!-- @@license=\"CC BY 2.0\" --><img decoding=\"async\" id=\"x-ck12-SFMtMDMtMDMtMTctUHlyaXRl\" title=\"\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/682\/2015\/07\/22223112\/201412291419878202719844_9388297cfc28d73f8b738f8f4d295831-201412291419879636088732.jpg\" alt=\"\" longdesc=\"This%20mineral%20has%20shiny%2C%20gold%2C%20cubic%20crystals%20with%20striations%2C%20so%20it%20is%20pyrite.%20\" \/>This mineral has shiny, gold, cubic crystals with striations, so it is pyrite.<\/p>\n<\/div>\n<h2>Color, Streak, and Luster<\/h2>\n<p>Diamonds are popular gemstones because the way they reflect light makes them very sparkly. Turquoise is prized for its striking greenish-blue color. Notice that specific terms are being used to describe the appearance of minerals.<\/p>\n<h3>Color<\/h3>\n<p>Color is rarely very useful for identifying a mineral. Different minerals may be the same color. Real gold, as seen in <strong>Figure<\/strong> <a href=\"#x-ck12-SFMtRVMtMDMtMDMtMTgtR29sZA..\">below<\/a>, is very similar in color to the pyrite in <strong>Figure<\/strong> <a href=\"#x-ck12-SFMtMDMtMDMtMTctUHlyaXRl\">above<\/a>.<\/p>\n<div class=\"x-ck12-img-postcard x-ck12-nofloat\"><!-- @@author=\"Aram Dulyan\" --><!-- @@url=\"http:\/\/commons.wikimedia.org\/wiki\/File:Native_gold_nuggets.jpg\" --><!-- @@license=\"Public Domain\" --><img decoding=\"async\" id=\"x-ck12-SFMtRVMtMDMtMDMtMTgtR29sZA..\" title=\"Gold nugget\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/682\/2015\/07\/22223114\/201412291419878202762390_b9bf3347e3f12c1f7a54efaa1981da6f-201412291419879636757698.jpg\" alt=\"Gold nugget\" longdesc=\"This%20mineral%20is%20shiny%2C%20very%20soft%2C%20heavy%2C%20and%20gold%20in%20color%2C%20and%20is%20actually%20gold.%20\" \/>This mineral is shiny, very soft, heavy, and gold in color, and is actually gold.<\/p>\n<\/div>\n<p>The same mineral may also be found in different colors. <strong>Figure<\/strong> <a href=\"#x-ck12-TVMtRVMtMDMtUXVhcnR6IGNvbXBvc2l0ZS5wbmc.\">below<\/a> shows one sample of quartz that is colorless and another quartz that is purple. A tiny amount of iron makes the quartz purple. Many minerals are colored by chemical impurities.<\/p>\n<div class=\"x-ck12-img-postcard x-ck12-nofloat\"><!-- @@author=\"Left: Stephanie Clifford; Right: Mauro Cateb\" --><!-- @@url=\"Left: http:\/\/www.flickr.com\/photos\/30486689@N08\/2933050796\/; Right: http:\/\/www.flickr.com\/photos\/mauroescritor\/6544435963\/\" --><!-- @@license=\"CC BY 2.0\" --><img decoding=\"async\" id=\"x-ck12-TVMtRVMtMDMtUXVhcnR6IGNvbXBvc2l0ZS5wbmc.\" title=\"\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/682\/2015\/07\/22223115\/201412291419878202777650_bd5b64fdcb63ee913c631dacfe378741-201412291419879637113499.jpg\" alt=\"\" longdesc=\"Purple%20quartz%2C%20known%20as%20amethyst%2C%20and%20clear%20quartz%20are%20the%20same%20mineral%20despite%20the%20different%20colors.%20\" \/>Purple quartz, known as amethyst, and clear quartz are the same mineral despite the different colors.<\/p>\n<\/div>\n<h3>Streak<\/h3>\n<p><strong>Streak<\/strong> is the color of a mineral\u2019s powder. Streak is a more reliable property than color because streak does not vary. Minerals that are the same color may have a different colored streak. Many minerals, such as the quartz in the <strong>Figure<\/strong> <a href=\"#x-ck12-TVMtRVMtMDMtUXVhcnR6IGNvbXBvc2l0ZS5wbmc.\">above<\/a>, do not have streak.<\/p>\n<p>To check streak, scrape the mineral across an unglazed porcelain plate (<strong>Figure<\/strong> <a href=\"#x-ck12-SFMtRVMtMDMtMDMtMjAtU3RyZWFraW5nLWhlbWF0aXRl\">below<\/a>). Yellow-gold pyrite has a blackish streak, another indicator that pyrite is not gold, which has a golden yellow streak.<\/p>\n<div class=\"x-ck12-img-postcard x-ck12-nofloat\"><!-- @@author=\"CK-12 Foundation\" --><!-- @@url=\"CK-12 Foundation\" --><!-- @@license=\"CC BY-NC 3.0\" --><img decoding=\"async\" id=\"x-ck12-SFMtRVMtMDMtMDMtMjAtU3RyZWFraW5nLWhlbWF0aXRl\" title=\"\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/682\/2015\/07\/22223116\/201412291419878202792910_856678cdab5a2d4e49c6292a9a950476-201412291419879638252191.jpg\" alt=\"\" longdesc=\"The%20streak%20of%20hematite%20across%20an%20unglazed%20porcelain%20plate%20is%20red-brown.%20\" \/>The streak of hematite across an unglazed porcelain plate is red-brown.<\/p>\n<\/div>\n<h3>Luster<\/h3>\n<p><strong>Luster<\/strong> describes the reflection of light off a mineral\u2019s surface. Mineralogists have special terms to describe luster. One simple way to classify luster is based on whether the mineral is metallic or non-metallic. Minerals that are opaque and shiny, such as pyrite, have a metallic luster. Minerals such as quartz have a non-metallic luster. Different types of non-metallic luster are described in <strong>Table<\/strong> <a href=\"#x-ck12-dGFibGU6bHVzdGVy\">below<\/a>.<\/p>\n<table id=\"x-ck12-dGFibGU6bHVzdGVy\" title=\"Six types of non-metallic luster\" summary=\"Six types of non-metallic luster\">\n<caption>Six types of non-metallic luster.<\/caption>\n<thead>\n<tr>\n<th><strong>Luster<\/strong><\/th>\n<th><strong>Appearance<\/strong><\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Adamantine<\/td>\n<td>Sparkly<\/td>\n<\/tr>\n<tr>\n<td>Earthy<\/td>\n<td>Dull, clay-like<\/td>\n<\/tr>\n<tr>\n<td>Pearly<\/td>\n<td>Pearl-like<\/td>\n<\/tr>\n<tr>\n<td>Resinous<\/td>\n<td>Like resins, such as tree sap<\/td>\n<\/tr>\n<tr>\n<td>Silky<\/td>\n<td>Soft-looking with long fibers<\/td>\n<\/tr>\n<tr>\n<td>Vitreous<\/td>\n<td>Glassy<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>Can you match the minerals in <strong>Figure<\/strong> <a href=\"#x-ck12-SFMtRVMtMDMtMDMtMjEtRGlhbW9uZC1xdWFydHotc3VsZnVy\">below<\/a> with the correct luster from <strong>Table<\/strong> <a href=\"#x-ck12-dGFibGU6bHVzdGVy\">above<\/a>?<\/p>\n<div class=\"x-ck12-img-fullpage x-ck12-nofloat\"><!-- @@author=\"(a) Flickr:Glass and Mirror; (b) Courtesy of the US Geological Survey; (c) Courtesy of Smithsonian Institution\" --><!-- @@url=\"(a) http:\/\/www.flickr.com\/photos\/hokaicila\/1543565434\/; (b) http:\/\/commons.wikimedia.org\/wiki\/File:Quartz_Crystal.jpg; (c) http:\/\/commons.wikimedia.org\/wiki\/File:Sulfur.jpg\" --><!-- @@license=\"(a) CC BY 2.0, (b) Public Domain; (c) Public Domain\" --><img decoding=\"async\" id=\"x-ck12-SFMtRVMtMDMtMDMtMjEtRGlhbW9uZC1xdWFydHotc3VsZnVy\" title=\"\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/682\/2015\/07\/22223118\/201412291419878202812429_9c45a8fcfdd91cecb7eb9d79743fedd2-201412291419879638691972.jpg\" alt=\"\" longdesc=\"%28a%29%20Diamond%20has%20an%20adamantine%20luster.%20%28b%29%20Quartz%20is%20not%20sparkly%20and%20has%20a%20vitreous%2C%20or%20glassy%2C%20luster.%20%28b%29%20Sulfur%20reflects%20less%20light%20than%20quartz%2C%20so%20it%20has%20a%20resinous%20luster.%20\" \/>(a) Diamond has an adamantine luster. (b) Quartz is not sparkly and has a vitreous, or glassy, luster. (b) Sulfur reflects less light than quartz, so it has a resinous luster.<\/p>\n<\/div>\n<h2>Specific Gravity<\/h2>\n<p><strong>Density<\/strong> describes how much matter is in a certain amount of space: density = mass\/volume.<\/p>\n<p>Mass is a measure of the amount of matter in an object. The amount of space an object takes up is described by its volume. The density of an object depends on its mass and its volume. For example, the water in a drinking glass has the same density as the water in the same volume of a swimming pool.<\/p>\n<p>Gold has a density of about 19 g\/cm<sup>3<\/sup>; pyrite has a density of about 5 g\/cm<sup>3<\/sup> &#8211; that\u2019s another way to tell pyrite from gold. Quartz is even less dense than pyrite and has a density of 2.7 g\/cm<sup>3<\/sup>.<\/p>\n<p>The specific gravity of a substance compares its density to that of water. Substances that are more dense have higher specific gravity.<\/p>\n<h2>Hardness<\/h2>\n<p><strong>Hardness<\/strong> is a measure of whether a mineral will scratch or be scratched. Mohs Hardness Scale, shown in <strong>Table<\/strong> <a href=\"#x-ck12-dGFibGU6aGFyZG5lc3M.\">below<\/a>, is a reference for mineral hardness.<\/p>\n<table id=\"x-ck12-dGFibGU6aGFyZG5lc3M.\" title=\"Mohs Hardness Scale: 1 (softest) to 10 (hardest)\" summary=\"Mohs Hardness Scale: 1 (softest) to 10 (hardest)\">\n<caption>Mohs Hardness Scale: 1 (softest) to 10 (hardest).<\/caption>\n<thead>\n<tr>\n<th><strong>Hardness<\/strong><\/th>\n<th><strong>Mineral<\/strong><\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>1<\/td>\n<td>Talc<\/td>\n<\/tr>\n<tr>\n<td>2<\/td>\n<td>Gypsum<\/td>\n<\/tr>\n<tr>\n<td>3<\/td>\n<td>Calcite<\/td>\n<\/tr>\n<tr>\n<td>4<\/td>\n<td>Fluorite<\/td>\n<\/tr>\n<tr>\n<td>5<\/td>\n<td>Apatite<\/td>\n<\/tr>\n<tr>\n<td>6<\/td>\n<td>Feldspar<\/td>\n<\/tr>\n<tr>\n<td>7<\/td>\n<td>Quartz<\/td>\n<\/tr>\n<tr>\n<td>8<\/td>\n<td>Topaz<\/td>\n<\/tr>\n<tr>\n<td>9<\/td>\n<td>Corundum<\/td>\n<\/tr>\n<tr>\n<td>10<\/td>\n<td>Diamond<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>With a Mohs scale, anyone can test an unknown mineral for its hardness. Imagine you have an unknown mineral. You find that it can scratch fluorite or even apatite, but feldspar scratches it. You know then that the mineral\u2019s hardness is between 5 and 6. Note that no other mineral can scratch diamond.<\/p>\n<h2>Cleavage and Fracture<\/h2>\n<p>Breaking a mineral breaks its chemical bonds. Since some bonds are weaker than other bonds, each type of mineral is likely to break where the bonds between the atoms are weaker. For that reason, minerals break apart in characteristic ways.<\/p>\n<p><strong>Cleavage<\/strong> is the tendency of a mineral to break along certain planes to make smooth surfaces. Halite breaks between layers of sodium and chlorine to form cubes with smooth surfaces (<strong>Figure<\/strong> <a href=\"#x-ck12-SFMtRVMtMDMtMDMtMjItU29kaXVtLWNobG9yaWRlLXdhdGVyLXNwYWNl\">below<\/a>).<\/p>\n<div class=\"x-ck12-img-thumbnail x-ck12-nofloat\"><!-- @@author=\"Courtesy of NASA\" --><!-- @@url=\"http:\/\/www.nasa.gov\/multimedia\/imagegallery\/image_feature_1561.html\" --><!-- @@license=\"Public Domain\" --><img decoding=\"async\" id=\"x-ck12-SFMtRVMtMDMtMDMtMjItU29kaXVtLWNobG9yaWRlLXdhdGVyLXNwYWNl\" title=\"\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/682\/2015\/07\/22223119\/201412291419878202835973_695cf6ad3bef2a183d1036b53cabb4ab-201412291419879639152658.jpg\" alt=\"\" longdesc=\"A%20close-up%20view%20of%20sodium%20chloride%20in%20a%20water%20bubble%20aboard%20the%20International%20Space%20Station.%20\" \/>A close-up view of sodium chloride in a water bubble aboard the International Space Station.<\/p>\n<\/div>\n<p>Mica has cleavage in one direction and forms sheets (<strong>Figure<\/strong> <a href=\"#x-ck12-SFMtRVMtMDMtMDMtMjMtTWljYS1zaGVldA..\">below<\/a>).<\/p>\n<div class=\"x-ck12-img-postcard x-ck12-nofloat\"><!-- @@author=\"User:\u0e19\u0e31\u0e19\u0e17\u0e20\u0e23\u0e13\u0e4c \u0e19\u0e34\u0e22\u0e21\u0e1a\u0e27\u0e23\u0e27\u0e31\u0e12\u0e19\u0e4c\/Wikimedia Commons\" --><!-- @@url=\"http:\/\/commons.wikimedia.org\/wiki\/File:Nanta-aom1.jpg\" --><!-- @@license=\"Public Domain\" --><img decoding=\"async\" id=\"x-ck12-SFMtRVMtMDMtMDMtMjMtTWljYS1zaGVldA..\" title=\"\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/682\/2015\/07\/22223120\/201412291419878202915236_2ae989336045c4b365a1a4d5bea260f2-201412291419879639839674.jpg\" alt=\"\" longdesc=\"Sheets%20of%20mica.%20\" \/>Sheets of mica.<\/p>\n<\/div>\n<p>Minerals can cleave into polygons. Fluorite forms octahedrons (<strong>Figure<\/strong> <a href=\"#x-ck12-SFMtRVMtMDMtMjQtRmx1b3JpdGUtb2N0YWhlZHJhbC1jbGVhdmFnZQ..\">below<\/a>).<\/p>\n<div class=\"x-ck12-img-thumbnail x-ck12-nofloat\"><!-- @@author=\"\" --><!-- @@url=\"http:\/\/commons.wikimedia.org\/wiki\/File:Rough_diamond_-_hardest_known_mineral.jpg\" --><!-- @@license=\"Public Domain\" --><img decoding=\"async\" id=\"x-ck12-SFMtRVMtMDMtMjQtRmx1b3JpdGUtb2N0YWhlZHJhbC1jbGVhdmFnZQ..\" title=\"\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/682\/2015\/07\/22223122\/201412291419878202930202_b1344dae2cb72feb80d266f3474f834b-201412291419879640439931.jpg\" alt=\"\" longdesc=\"This%20rough%20diamond%20shows%20its%20octahedral%20cleavage.%20\" \/>This rough diamond shows its octahedral cleavage.<\/p>\n<\/div>\n<p>One reason gemstones are beautiful is that the cleavage planes make an attractive crystal shape with smooth faces.<\/p>\n<p><strong>Fracture<\/strong> is a break in a mineral that is not along a cleavage plane. Fracture is not always the same in the same mineral because fracture is not determined by the structure of the mineral.<\/p>\n<p>Minerals may have characteristic fractures (<strong>Figure<\/strong> <a href=\"#x-ck12-SFMtRVMtMDMtMDMtMjUtQ2hyeXNvdGlsZS1zcGxpbnRlcnk.\">below<\/a>). Metals usually fracture into jagged edges. If a mineral splinters like wood, it may be fibrous. Some minerals, such as quartz, form smooth curved surfaces when they fracture.<\/p>\n<div class=\"x-ck12-img-postcard x-ck12-nofloat\"><!-- @@author=\"Courtesy of Andrew Silver, USGS\" --><!-- @@url=\"http:\/\/commons.wikimedia.org\/wiki\/File:Chrysotile_-_USGS_Mineral_Specimens_302.jpg\" --><!-- @@license=\"Public Domain\" --><img decoding=\"async\" id=\"x-ck12-SFMtRVMtMDMtMDMtMjUtQ2hyeXNvdGlsZS1zcGxpbnRlcnk.\" title=\"\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/682\/2015\/07\/22223123\/201412291419878202946102_984fbcdf364b4520f8da6f2e7cc98c91-201412291419879640928735.jpg\" alt=\"\" longdesc=\"Chrysotile%20has%20splintery%20fracture.%20\" \/>Chrysotile has splintery fracture.<\/p>\n<\/div>\n<h2>Other Identifying Characteristics<\/h2>\n<p>Some minerals have other unique properties, some of which are listed in <strong>Table<\/strong> <a href=\"#x-ck12-dGFibGU6aWRlbnRpZmllcnM.\">below<\/a>. Can you name a unique property that would allow you to instantly identify a mineral that\u2019s been described quite a bit in this chapter? (Hint: It is most likely found on your dinner table.)<\/p>\n<table id=\"x-ck12-dGFibGU6aWRlbnRpZmllcnM.\" title=\"Unique Identifying Mineral Properties\" summary=\"Unique Identifying Mineral Properties\">\n<caption>Some minerals have unusual properties that can be used for identification.<\/caption>\n<thead>\n<tr>\n<th><strong>Property<\/strong><\/th>\n<th><strong>Description<\/strong><\/th>\n<th><strong>Example of Mineral<\/strong><\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Fluorescence<\/td>\n<td>Mineral glows under ultraviolet light<\/td>\n<td>Fluorite<\/td>\n<\/tr>\n<tr>\n<td>Magnetism<\/td>\n<td>Mineral is attracted to a magnet<\/td>\n<td>Magnetite<\/td>\n<\/tr>\n<tr>\n<td>Radioactivity<\/td>\n<td>Mineral gives off radiation that can be measured with Geiger counter<\/td>\n<td>Uraninite<\/td>\n<\/tr>\n<tr>\n<td>Reactivity<\/td>\n<td>Bubbles form when mineral is exposed to a weak acid<\/td>\n<td>Calcite<\/td>\n<\/tr>\n<tr>\n<td>Smell<\/td>\n<td>Some minerals have a distinctive smell<\/td>\n<td>Sulfur (smells like rotten eggs)<\/td>\n<\/tr>\n<tr>\n<td>Taste<\/td>\n<td>Some minerals taste salty<\/td>\n<td>Halite<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>A simple lesson on how to identify minerals is seen in this video.<\/p>\n<h2>Lesson Summary<\/h2>\n<ul>\n<li>Minerals have distinctive properties that can be used to help identify them.<\/li>\n<li>Color and luster describe the mineral\u2019s outer appearance. Streak is the color of the powder.<\/li>\n<li>A mineral has a characteristic density.<\/li>\n<li>Mohs Hardness Scale is used to compare the hardness of minerals.<\/li>\n<li>Cleavage or the characteristic way a mineral breaks depends on the crystal structure of the mineral.<\/li>\n<li>Some minerals have special properties that can be used to help identify them.<\/li>\n<\/ul>\n<h2>Review Questions<\/h2>\n<ol id=\"x-ck12-ODIyMDNjNjE2ZTQxMTk3NTA4ZThiMGE1ZjRlMTdmNjc.-dez\" class=\"x-ck12-decimal\">\n<li>Which properties of a mineral describe the way it breaks apart?<\/li>\n<li>A mineral looks dry and chalky. What sort of luster does it have?<\/li>\n<li>What causes a mineral to have the properties that it has?<\/li>\n<li>Apatite scratches the surface of an unknown mineral. Which mineral would you use next to test the mineral\u2019s hardness \u2014 fluorite or feldspar? Explain your reasoning.<\/li>\n<li>Why is streak more reliable than color when identifying a mineral?<\/li>\n<li>Mineral A has a density of 5 g\/cm<sup>3<\/sup>. Mineral B is twice as dense as Mineral A. What is the density of Mineral B?<\/li>\n<li>Why do some minerals cleave along certain planes?<\/li>\n<\/ol>\n<h2>Further Reading \/ Supplemental Links<\/h2>\n<ul>\n<li><a href=\"http:\/\/geology.csupomona.edu\/alert\/mineral\/color.htm\/\">Mineral Color<\/a><\/li>\n<li><a href=\"http:\/\/www.galleries.com\/minerals\/physical.htm\">Physical Characteristics of Minerals<\/a>.<\/li>\n<li><a href=\"http:\/\/geology.csupomona.edu\/alert\/mineral\/minerals.htm\">Mineral Identification<\/a>.<\/li>\n<\/ul>\n<h2>Points to Consider<\/h2>\n<ul>\n<li>If a mineral is magnetic, do you know for certain what mineral it is?<\/li>\n<li>Some minerals are colored because they contain chemical impurities. How did the impurities get into the mineral?<\/li>\n<li>What two properties of a mineral sample would you have to measure to calculate its density?<\/li>\n<li>How much do minerals reflect the environment in which they formed?<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n\n\t\t\t <section class=\"citations-section\" role=\"contentinfo\">\n\t\t\t <h3>Candela Citations<\/h3>\n\t\t\t\t\t <div>\n\t\t\t\t\t\t <div id=\"citation-list-109\">\n\t\t\t\t\t\t\t <div class=\"licensing\"><div class=\"license-attribution-dropdown-subheading\">CC licensed content, Shared previously<\/div><ul class=\"citation-list\"><li>Earth Science for High School. <strong>Provided by<\/strong>: CK-12. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"http:\/\/www.ck12.org\/book\/CK-12-Earth-Science-For-High-School\/\">http:\/\/www.ck12.org\/book\/CK-12-Earth-Science-For-High-School\/<\/a>. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/\">CC BY-NC: Attribution-NonCommercial<\/a><\/em><\/li><\/ul><\/div>\n\t\t\t\t\t\t <\/div>\n\t\t\t\t\t <\/div>\n\t\t\t <\/section>","protected":false},"author":277,"menu_order":6,"template":"","meta":{"_candela_citation":"[{\"type\":\"cc\",\"description\":\"Earth Science for High School\",\"author\":\"\",\"organization\":\"CK-12\",\"url\":\"http:\/\/www.ck12.org\/book\/CK-12-Earth-Science-For-High-School\/\",\"project\":\"\",\"license\":\"cc-by-nc\",\"license_terms\":\"\"}]","CANDELA_OUTCOMES_GUID":"","pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-109","chapter","type-chapter","status-publish","hentry"],"part":1291,"_links":{"self":[{"href":"https:\/\/courses.lumenlearning.com\/earthscienceck12\/wp-json\/pressbooks\/v2\/chapters\/109","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/courses.lumenlearning.com\/earthscienceck12\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/courses.lumenlearning.com\/earthscienceck12\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/earthscienceck12\/wp-json\/wp\/v2\/users\/277"}],"version-history":[{"count":4,"href":"https:\/\/courses.lumenlearning.com\/earthscienceck12\/wp-json\/pressbooks\/v2\/chapters\/109\/revisions"}],"predecessor-version":[{"id":1323,"href":"https:\/\/courses.lumenlearning.com\/earthscienceck12\/wp-json\/pressbooks\/v2\/chapters\/109\/revisions\/1323"}],"part":[{"href":"https:\/\/courses.lumenlearning.com\/earthscienceck12\/wp-json\/pressbooks\/v2\/parts\/1291"}],"metadata":[{"href":"https:\/\/courses.lumenlearning.com\/earthscienceck12\/wp-json\/pressbooks\/v2\/chapters\/109\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/courses.lumenlearning.com\/earthscienceck12\/wp-json\/wp\/v2\/media?parent=109"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/earthscienceck12\/wp-json\/pressbooks\/v2\/chapter-type?post=109"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/earthscienceck12\/wp-json\/wp\/v2\/contributor?post=109"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/earthscienceck12\/wp-json\/wp\/v2\/license?post=109"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}