{"id":902,"date":"2017-11-27T16:30:03","date_gmt":"2017-11-27T16:30:03","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/ivytech-sci111\/chapter\/mineral-identification\/"},"modified":"2020-05-11T09:50:00","modified_gmt":"2020-05-11T09:50:00","slug":"mineral-identification","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/ivytech-sci111\/chapter\/mineral-identification\/","title":{"raw":"Module 11 Mineral Identification","rendered":"Module 11 Mineral Identification"},"content":{"raw":"<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>Explain how the hardness of a mineral is measured.<\/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>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>\u00a0are 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\u00a0<strong>Figure<\/strong>\u00a0 below. 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>\r\n\r\n<a href=\"https:\/\/s3-us-west-2.amazonaws.com\/candimgs\/7R0xzU\/f-d3555746f1f5377114c79bed0af1303dba9ffca591cf14e197c69d6e4IMAGE_THUMB_POSTCARDIMAGE_THUMB_POSTCARD.1\"><img title=\"\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/candimgs\/7R0xzU\/f-d3555746f1f5377114c79bed0af1303dba9ffca591cf14e197c69d6e4IMAGE_THUMB_POSTCARDIMAGE_THUMB_POSTCARD.1#fixme\" alt=\"\" longdesc=\"#This%20mineral%20has%20shiny%2C%20gold%2C%20cubic%20crystals%20with%20striations%2C%20so%20it%20is%20pyrite.%20\" \/><\/a>\r\n\r\nThis 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\u00a0<strong>Figure<\/strong>\u00a0 below, is very similar in color to the pyrite in\u00a0<strong>Figure<\/strong>\u00a0<a href=\"#x-ck12-SFMtMDMtMDMtMTctUHlyaXRl\">above<\/a>.\r\n<div>\r\n\r\n<a href=\"https:\/\/s3-us-west-2.amazonaws.com\/candimgs\/7R0xzU\/f-d0f479c9542399bb4f0750e248573fd6de0a77747a1827398e88bb0edIMAGE_THUMB_POSTCARDIMAGE_THUMB_POSTCARD.1\"><img title=\"Gold nugget\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/candimgs\/7R0xzU\/f-d0f479c9542399bb4f0750e248573fd6de0a77747a1827398e88bb0edIMAGE_THUMB_POSTCARDIMAGE_THUMB_POSTCARD.1#fixme\" alt=\"Gold nugget\" longdesc=\"#This%20mineral%20is%20shiny%2C%20very%20soft%2C%20heavy%2C%20and%20gold%20in%20color%2C%20and%20is%20actually%20gold.%20\" \/><\/a>\r\n\r\nThis 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.\u00a0<strong>Figure<\/strong>\u00a0 below\u00a0shows 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>\r\n\r\n<a href=\"https:\/\/s3-us-west-2.amazonaws.com\/candimgs\/7R0xzU\/f-d8cd7e3ecd948eebb2972634c60a69fbf181a513e2939e3f01c68fa5cIMAGE_THUMB_POSTCARDIMAGE_THUMB_POSTCARD.1\"><img title=\"\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/candimgs\/7R0xzU\/f-d8cd7e3ecd948eebb2972634c60a69fbf181a513e2939e3f01c68fa5cIMAGE_THUMB_POSTCARDIMAGE_THUMB_POSTCARD.1#fixme\" alt=\"\" longdesc=\"#Purple%20quartz%2C%20known%20as%20amethyst%2C%20and%20clear%20quartz%20are%20the%20same%20mineral%20despite%20the%20different%20colors.%20\" \/><\/a>\r\n\r\nPurple 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>\u00a0is 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\u00a0<strong>Figure<\/strong>\u00a0<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>\u00a0 below). Yellow-gold pyrite has a blackish streak, another indicator that pyrite is not gold, which has a golden yellow streak.\r\n<div>\r\n\r\n<a href=\"https:\/\/s3-us-west-2.amazonaws.com\/candimgs\/7R0xzU\/f-d88252bcc1fb6ea4613ef8d2f2906d6c4e11894f2d7b9e6798d890456IMAGE_THUMB_POSTCARDIMAGE_THUMB_POSTCARD.1\"><img title=\"\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/candimgs\/7R0xzU\/f-d88252bcc1fb6ea4613ef8d2f2906d6c4e11894f2d7b9e6798d890456IMAGE_THUMB_POSTCARDIMAGE_THUMB_POSTCARD.1#fixme\" alt=\"\" longdesc=\"#The%20streak%20of%20hematite%20across%20an%20unglazed%20porcelain%20plate%20is%20red-brown.%20\" \/><\/a>\r\n\r\nThe 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>\u00a0describes 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\u00a0<strong>Table<\/strong>\u00a0 below.\r\n<table 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\n<h2><\/h2>\r\n<strong>Hardness<\/strong>\u00a0is a measure of whether a mineral will scratch or be scratched. Mohs Hardness Scale, shown in\u00a0<strong>Table<\/strong>\u00a0 below, is a reference for mineral hardness.\r\n<table 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>\u00a0is 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>\u00a0 below).\r\n<div>\r\n\r\n<a href=\"https:\/\/s3-us-west-2.amazonaws.com\/candimgs\/7R0xzU\/f-dac57f2ac6db08f5f42ec042f349f4d1051ccd6a2fbd63be313fedf3dIMAGE_THUMB_LARGEIMAGE_THUMB_LARGE.1\"><img title=\"\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/candimgs\/7R0xzU\/f-dac57f2ac6db08f5f42ec042f349f4d1051ccd6a2fbd63be313fedf3dIMAGE_THUMB_LARGEIMAGE_THUMB_LARGE.1#fixme\" alt=\"\" longdesc=\"#A%20close-up%20view%20of%20sodium%20chloride%20in%20a%20water%20bubble%20aboard%20the%20International%20Space%20Station.%20\" \/><\/a>\r\n\r\nA 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>\u00a0 below).\r\n<div>\r\n\r\n<a href=\"https:\/\/s3-us-west-2.amazonaws.com\/candimgs\/7R0xzU\/f-d2a9ac7cf0f700e6135e172143d77c0e838394d67fead7b897484ae11IMAGE_THUMB_POSTCARDIMAGE_THUMB_POSTCARD.1\"><img title=\"\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/candimgs\/7R0xzU\/f-d2a9ac7cf0f700e6135e172143d77c0e838394d67fead7b897484ae11IMAGE_THUMB_POSTCARDIMAGE_THUMB_POSTCARD.1#fixme\" alt=\"\" longdesc=\"#Sheets%20of%20mica.%20\" \/><\/a>\r\n\r\nSheets of mica.\r\n\r\n<\/div>\r\nMinerals can cleave into polygons. Fluorite forms octahedrons (<strong>Figure<\/strong>\u00a0 below).\r\n<div>\r\n\r\n<a href=\"https:\/\/s3-us-west-2.amazonaws.com\/candimgs\/7R0xzU\/f-db9489daf5e6472eb002f5531f14261109d7c6fde0c7649145df2ec22IMAGE_THUMB_LARGEIMAGE_THUMB_LARGE.1\"><img title=\"\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/candimgs\/7R0xzU\/f-db9489daf5e6472eb002f5531f14261109d7c6fde0c7649145df2ec22IMAGE_THUMB_LARGEIMAGE_THUMB_LARGE.1#fixme\" alt=\"\" longdesc=\"#This%20rough%20diamond%20shows%20its%20octahedral%20cleavage.%20\" \/><\/a>\r\n\r\nThis 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>\u00a0is 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>\u00a0 below). 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>\r\n\r\n<a href=\"https:\/\/s3-us-west-2.amazonaws.com\/candimgs\/7R0xzU\/f-d1cd85c4bf9c4dbcf89b94eac19e07e81dc5762d608be7484cef5d04eIMAGE_THUMB_POSTCARDIMAGE_THUMB_POSTCARD.1\"><img title=\"\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/candimgs\/7R0xzU\/f-d1cd85c4bf9c4dbcf89b94eac19e07e81dc5762d608be7484cef5d04eIMAGE_THUMB_POSTCARDIMAGE_THUMB_POSTCARD.1#fixme\" alt=\"\" longdesc=\"#Chrysotile%20has%20splintery%20fracture.%20\" \/><\/a>\r\n\r\nChrysotile 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\u00a0<strong>Table<\/strong>\u00a0 below. 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 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:\u00a0<a href=\"http:\/\/www.youtube.com\/watch?v=JeFVwqBuYl4\">http:\/\/www.youtube.com\/watch?v=JeFVwqBuYl4<\/a>.\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>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>\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>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>","rendered":"<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>Explain how the hardness of a mineral is measured.<\/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>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>\u00a0are 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\u00a0<strong>Figure<\/strong>\u00a0 below. 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>\n<p><a href=\"https:\/\/s3-us-west-2.amazonaws.com\/candimgs\/7R0xzU\/f-d3555746f1f5377114c79bed0af1303dba9ffca591cf14e197c69d6e4IMAGE_THUMB_POSTCARDIMAGE_THUMB_POSTCARD.1\"><img decoding=\"async\" title=\"\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/candimgs\/7R0xzU\/f-d3555746f1f5377114c79bed0af1303dba9ffca591cf14e197c69d6e4IMAGE_THUMB_POSTCARDIMAGE_THUMB_POSTCARD.1#fixme\" alt=\"\" longdesc=\"#This%20mineral%20has%20shiny%2C%20gold%2C%20cubic%20crystals%20with%20striations%2C%20so%20it%20is%20pyrite.%20\" \/><\/a><\/p>\n<p>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\u00a0<strong>Figure<\/strong>\u00a0 below, is very similar in color to the pyrite in\u00a0<strong>Figure<\/strong>\u00a0<a href=\"#x-ck12-SFMtMDMtMDMtMTctUHlyaXRl\">above<\/a>.<\/p>\n<div>\n<p><a href=\"https:\/\/s3-us-west-2.amazonaws.com\/candimgs\/7R0xzU\/f-d0f479c9542399bb4f0750e248573fd6de0a77747a1827398e88bb0edIMAGE_THUMB_POSTCARDIMAGE_THUMB_POSTCARD.1\"><img decoding=\"async\" title=\"Gold nugget\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/candimgs\/7R0xzU\/f-d0f479c9542399bb4f0750e248573fd6de0a77747a1827398e88bb0edIMAGE_THUMB_POSTCARDIMAGE_THUMB_POSTCARD.1#fixme\" alt=\"Gold nugget\" longdesc=\"#This%20mineral%20is%20shiny%2C%20very%20soft%2C%20heavy%2C%20and%20gold%20in%20color%2C%20and%20is%20actually%20gold.%20\" \/><\/a><\/p>\n<p>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.\u00a0<strong>Figure<\/strong>\u00a0 below\u00a0shows 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>\n<p><a href=\"https:\/\/s3-us-west-2.amazonaws.com\/candimgs\/7R0xzU\/f-d8cd7e3ecd948eebb2972634c60a69fbf181a513e2939e3f01c68fa5cIMAGE_THUMB_POSTCARDIMAGE_THUMB_POSTCARD.1\"><img decoding=\"async\" title=\"\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/candimgs\/7R0xzU\/f-d8cd7e3ecd948eebb2972634c60a69fbf181a513e2939e3f01c68fa5cIMAGE_THUMB_POSTCARDIMAGE_THUMB_POSTCARD.1#fixme\" alt=\"\" longdesc=\"#Purple%20quartz%2C%20known%20as%20amethyst%2C%20and%20clear%20quartz%20are%20the%20same%20mineral%20despite%20the%20different%20colors.%20\" \/><\/a><\/p>\n<p>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>\u00a0is 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\u00a0<strong>Figure<\/strong>\u00a0<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>\u00a0 below). Yellow-gold pyrite has a blackish streak, another indicator that pyrite is not gold, which has a golden yellow streak.<\/p>\n<div>\n<p><a href=\"https:\/\/s3-us-west-2.amazonaws.com\/candimgs\/7R0xzU\/f-d88252bcc1fb6ea4613ef8d2f2906d6c4e11894f2d7b9e6798d890456IMAGE_THUMB_POSTCARDIMAGE_THUMB_POSTCARD.1\"><img decoding=\"async\" title=\"\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/candimgs\/7R0xzU\/f-d88252bcc1fb6ea4613ef8d2f2906d6c4e11894f2d7b9e6798d890456IMAGE_THUMB_POSTCARDIMAGE_THUMB_POSTCARD.1#fixme\" alt=\"\" longdesc=\"#The%20streak%20of%20hematite%20across%20an%20unglazed%20porcelain%20plate%20is%20red-brown.%20\" \/><\/a><\/p>\n<p>The streak of hematite across an unglazed porcelain plate is red-brown.<\/p>\n<\/div>\n<h3>Luster<\/h3>\n<p><strong>Luster<\/strong>\u00a0describes 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\u00a0<strong>Table<\/strong>\u00a0 below.<\/p>\n<table 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<h2><\/h2>\n<p><strong>Hardness<\/strong>\u00a0is a measure of whether a mineral will scratch or be scratched. Mohs Hardness Scale, shown in\u00a0<strong>Table<\/strong>\u00a0 below, is a reference for mineral hardness.<\/p>\n<table 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>\u00a0is 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>\u00a0 below).<\/p>\n<div>\n<p><a href=\"https:\/\/s3-us-west-2.amazonaws.com\/candimgs\/7R0xzU\/f-dac57f2ac6db08f5f42ec042f349f4d1051ccd6a2fbd63be313fedf3dIMAGE_THUMB_LARGEIMAGE_THUMB_LARGE.1\"><img decoding=\"async\" title=\"\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/candimgs\/7R0xzU\/f-dac57f2ac6db08f5f42ec042f349f4d1051ccd6a2fbd63be313fedf3dIMAGE_THUMB_LARGEIMAGE_THUMB_LARGE.1#fixme\" alt=\"\" longdesc=\"#A%20close-up%20view%20of%20sodium%20chloride%20in%20a%20water%20bubble%20aboard%20the%20International%20Space%20Station.%20\" \/><\/a><\/p>\n<p>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>\u00a0 below).<\/p>\n<div>\n<p><a href=\"https:\/\/s3-us-west-2.amazonaws.com\/candimgs\/7R0xzU\/f-d2a9ac7cf0f700e6135e172143d77c0e838394d67fead7b897484ae11IMAGE_THUMB_POSTCARDIMAGE_THUMB_POSTCARD.1\"><img decoding=\"async\" title=\"\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/candimgs\/7R0xzU\/f-d2a9ac7cf0f700e6135e172143d77c0e838394d67fead7b897484ae11IMAGE_THUMB_POSTCARDIMAGE_THUMB_POSTCARD.1#fixme\" alt=\"\" longdesc=\"#Sheets%20of%20mica.%20\" \/><\/a><\/p>\n<p>Sheets of mica.<\/p>\n<\/div>\n<p>Minerals can cleave into polygons. Fluorite forms octahedrons (<strong>Figure<\/strong>\u00a0 below).<\/p>\n<div>\n<p><a href=\"https:\/\/s3-us-west-2.amazonaws.com\/candimgs\/7R0xzU\/f-db9489daf5e6472eb002f5531f14261109d7c6fde0c7649145df2ec22IMAGE_THUMB_LARGEIMAGE_THUMB_LARGE.1\"><img decoding=\"async\" title=\"\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/candimgs\/7R0xzU\/f-db9489daf5e6472eb002f5531f14261109d7c6fde0c7649145df2ec22IMAGE_THUMB_LARGEIMAGE_THUMB_LARGE.1#fixme\" alt=\"\" longdesc=\"#This%20rough%20diamond%20shows%20its%20octahedral%20cleavage.%20\" \/><\/a><\/p>\n<p>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>\u00a0is 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>\u00a0 below). 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>\n<p><a href=\"https:\/\/s3-us-west-2.amazonaws.com\/candimgs\/7R0xzU\/f-d1cd85c4bf9c4dbcf89b94eac19e07e81dc5762d608be7484cef5d04eIMAGE_THUMB_POSTCARDIMAGE_THUMB_POSTCARD.1\"><img decoding=\"async\" title=\"\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/candimgs\/7R0xzU\/f-d1cd85c4bf9c4dbcf89b94eac19e07e81dc5762d608be7484cef5d04eIMAGE_THUMB_POSTCARDIMAGE_THUMB_POSTCARD.1#fixme\" alt=\"\" longdesc=\"#Chrysotile%20has%20splintery%20fracture.%20\" \/><\/a><\/p>\n<p>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\u00a0<strong>Table<\/strong>\u00a0 below. 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 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:\u00a0<a href=\"http:\/\/www.youtube.com\/watch?v=JeFVwqBuYl4\">http:\/\/www.youtube.com\/watch?v=JeFVwqBuYl4<\/a>.<\/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>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>\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>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","protected":false},"author":17,"menu_order":3,"template":"","meta":{"_candela_citation":"[]","CANDELA_OUTCOMES_GUID":"","pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-902","chapter","type-chapter","status-publish","hentry"],"part":1079,"_links":{"self":[{"href":"https:\/\/courses.lumenlearning.com\/ivytech-sci111\/wp-json\/pressbooks\/v2\/chapters\/902","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/courses.lumenlearning.com\/ivytech-sci111\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/courses.lumenlearning.com\/ivytech-sci111\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/ivytech-sci111\/wp-json\/wp\/v2\/users\/17"}],"version-history":[{"count":4,"href":"https:\/\/courses.lumenlearning.com\/ivytech-sci111\/wp-json\/pressbooks\/v2\/chapters\/902\/revisions"}],"predecessor-version":[{"id":1979,"href":"https:\/\/courses.lumenlearning.com\/ivytech-sci111\/wp-json\/pressbooks\/v2\/chapters\/902\/revisions\/1979"}],"part":[{"href":"https:\/\/courses.lumenlearning.com\/ivytech-sci111\/wp-json\/pressbooks\/v2\/parts\/1079"}],"metadata":[{"href":"https:\/\/courses.lumenlearning.com\/ivytech-sci111\/wp-json\/pressbooks\/v2\/chapters\/902\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/courses.lumenlearning.com\/ivytech-sci111\/wp-json\/wp\/v2\/media?parent=902"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/ivytech-sci111\/wp-json\/pressbooks\/v2\/chapter-type?post=902"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/ivytech-sci111\/wp-json\/wp\/v2\/contributor?post=902"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/ivytech-sci111\/wp-json\/wp\/v2\/license?post=902"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}