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  • 矿物鉴定

    A blue shirt next to a blue mineral specimen, demonstrating physical property identification.
     

    How do you identify a mineral?
    ::你如何识别矿物质?

    You're in a  competition  getting ready to go onstage. You discover that you forgot your shirt! You call your mom and ask her (nicely) to bring it to you right away. But first you need to let her know which shirt it is. What would you tell her? You might describe the color, the way the fabric feels, and the length of the sleeves. These are all physical properties of your shirt. If you do a good job describing the shirt your mom will bring the right one.   also have physical properties that are used to identify them.
    ::你正在竞技中准备上台。 你发现你忘了你的衬衫。 你给你妈妈打电话, 让她马上给你。 但首先你需要让她知道这是哪件衬衫。 你会告诉她什么? 你可以描述颜色, 织物的感觉, 袖子的长度。 这些都是你衬衫的物理特性。 如果你做一个好的工作, 描述你妈妈的衬衫, 就会带来正确的衣服。 还有物理特性, 用来识别它们。

    How Are Minerals Identified?
    ::矿物是如何识别的?

    Imagine you were given a mineral sample similar to the one pictured below ( Figure   ). You can use a mineral’s properties to identify what type it is. How would you try to identify your mineral? You can observe some properties by looking at the mineral. For example, you can see that its color is green. The mineral has a needle-like, fibrous structure. But you can't see all mineral properties. You need to do simple tests to determine some properties, such as how hard the mineral is. The mineral’s physical properties are determined by its chemical composition and  crystal  structure.
    ::想象一下您得到的矿物质样本与下面所描绘的相似( 图 ) 。 您可以使用矿物质特性来识别矿物质的类型 。 您将如何尝试识别矿物质 ? 您可以通过查看矿物质观察一些属性 。 例如, 您可以看到矿物质的颜色是绿色的。 矿物质有像针一样的纤维结构。 但是, 您无法看到所有的矿物质特性 。 您需要做简单的测试来确定某些属性, 如矿物质有多难。 矿物质的物理特性取决于其化学成分和晶体结构 。

    A green, needle-like fibrous mineral sample resembling actinolite, highlighting its structural properties.
     
    Green actinolite.

    Color, Streak, and Luster
    ::颜色、 溪流、 鲁斯特

    Diamonds have many valuable properties. Diamonds are translucent and extremely hard. The most valuable diamonds are large, well-shaped and sparkly. Some are not as pretty and are used for industrial purposes. Turquoise is another mineral that is used in jewelry because of its striking greenish-blue color. Many minerals have interesting appearances. Specific terms are used to describe the appearance of minerals.
    ::钻石具有许多宝贵的特性,钻石是半透明、极其坚硬的,最有价值的钻石是大钻石、形状精美和闪亮的,有些不那么漂亮,用于工业目的,绿宝石是首饰中的另一个矿物,因其惊人的绿色蓝色颜色,许多矿物具有有趣的外观,具体术语用来描述矿物的外观。

    Color
    ::颜色颜色颜色

    Color is probably the easiest property to observe. Unfortunately, you can rarely identify a mineral only by its color. Sometimes, different minerals are the same color. For example, you might find a mineral that is a golden color and think it is gold. But it might actually be pyrite, or “fool's gold,” which is made of iron and  sulfide . It contains no gold atoms.
    ::颜色可能是最容易观察的属性。 不幸的是, 您很少能根据颜色来识别矿物质。 有时, 不同的矿物质是相同的颜色。 例如, 您可能找到金色的矿物质, 并会认为它是金色的。 但实际上它可能是铁和硫化物制成的金矿, 或者“ 泡沫的金矿 ” 。 它没有金原子。

    A certain mineral may form in different colors. For example, pictured below are four samples of quartz ( Figure    shows), including one that is colorless and one that is purple. The purple color comes from a tiny amount of iron. Iron is not normally found in quartz. When it is, it is a chemical impurity. Many minerals are colored by chemical impurities. Other factors can also affect a mineral’s color.  Weathering  changes the surface of a mineral. Because color alone is unreliable, geologists rarely identify a mineral just on its color. To identify most minerals, they use several properties.
    ::某些矿物质可能以不同颜色的形式形成。 例如, 下面的图画有四个石英样本( Figure shows) , 包括一个无色和紫色的样本。 紫色的样本来自少量铁。 通常在石英中找不到铁。 当它是化学杂质时, 它通常是化学杂质。 许多矿物质是化学杂质所染色的。 其他因素也可能影响矿物的颜色。 天气变化会改变矿物的表面。 由于光是颜色是不可靠的, 地质学家很少在颜色上识别矿物质。 为了识别大多数矿物质, 他们使用几种特性 。

    Four samples of quartz: clear, blue agate, rose, and purple amethyst, illustrating color diversity.
     
    Quartz comes in many different colors including: (A) transparent quartz, (B) blue agate, (C) rose quartz, and (D) purple amethyst.

    Streak
    ::堆叠

    Streak  is the color of the powder of a mineral. To do a streak test, you scrape the mineral across an unglazed porcelain  plate . The plate is harder than many minerals, causing the minerals to leave a streak of powder on the plate. The color of the streak often differs from the color of the larger mineral sample ( Figure   ). Yellow-gold pyrite has a blackish streak. This blackish streak tells you that the mineral is not gold, because gold has a gold-colored streak.
    ::堆积是矿物质粉色的颜色。 要进行连环测试, 您会将矿物质刮过一个粘结的瓷板板。 板比许多矿物质更难, 导致矿物质在板上留下一连串粉末。 串状的颜色通常与较大矿物质样品的颜色不同( 图表 ) 。 黄金色的金色有黑线。 这种黑线告诉您, 矿物质不是金色的, 因为金色有金色的条纹 。

    A person holding a mineral over an unglazed porcelain plate to conduct a streak test.
     
    Rub a mineral across an unglazed porcelain plate to see its streak. Hematite has a reddish-brown streak.

    Streak is more reliable than color to identify minerals. Different minerals that are the same color may have a different color streak. For example, samples of hematite and galena are both dark gray. They can be told apart because hematite has a red streak and galena has a gray streak.
    ::串列比颜色更可靠, 以识别矿物质。 不同颜色的矿物可能有不同的颜色。 例如, 希玛提和加莱纳的样本都是暗灰色的。 它们可以分解, 因为希玛提有红色, 加莱纳也有灰色的纹身 。

    Luster
    ::润滑

    Luster  describes the way light reflects off of the surface of the mineral. You might describe diamonds as sparkly or pyrite as shiny. But mineralogists have special terms to describe luster. They first  divide  minerals into metallic and non-metallic luster. Minerals that are opaque and shiny, like pyrite, are said to have a “metallic” luster. Minerals with a “non-metallic” luster do not look like metals. There are many types of non-metallic luster. Six are described below ( Table   ).
    ::卢斯特描述光线从矿物质表面反射的方式。 你可以将钻石描述成闪亮或闪亮。 但矿物学家有描述色质的特殊术语。 他们首先将矿物分为金属和非金属的色素。 与金矿一样,不透明且闪亮的矿物据说有“金属”色素。 带有“非金属”色素的矿物看起来不像金属。 有许多非金属色素的色素类型。 下文(表)描述六。

    Non-Metallic Luster Appearance
    Adamantine Sparkly
    Earthy Dull, clay-like
    Pearly Pearl-like
    Resinous Like resins, such as tree sap
    Silky Soft-looking with long fibers
    Vitreous Glassy

    Can you match the minerals ( Figure   ) with the correct luster, listed above ( Table   ), without looking at the caption?
    ::您能否在不看标题的情况下,将矿物质(图)与上表(表)所列正确的色素匹配?

    Various minerals showcasing different lusters for mineral identification study.
     
    (A) Diamonds have an adamantine luster. These minerals are transparent and highly reflective. (B) Kaolinite is a clay with a dull or earthy luster. (C) Opal’s luster is greasy. (D) Chalcopyrite, like its cousin pyrite, has metallic luster. (E) Stilbite (orange) has a resinous luster. (F) The white ulexite has silky luster. (G) Sphalerite has a submetallic luster. (H) Chert is a mineral with a waxy luster.

    Density
    ::密度

    You are going to visit a friend. You fill one backpack with books so you can study later. You stuff your pillow into another backpack that is the same size. Which backpack will be easier to carry? Even though the backpacks are the same size, the bag that contains your books is going to be much heavier. It has a greater density than the backpack with your pillow.
    ::你要去拜访一个朋友。 你用一个背包填满一个书包, 这样你就可以学习了。 你把你的枕头塞进另一个大小相同的背包里。 哪个背包比较容易搬? 即使背包的大小相同, 书包里装书的包会更重。 它比枕头背包的密度要大得多。

    Density  describes how much matter is in a certain amount of space. Substances that have more matter packed into a given space have higher densities. The  water  in a drinking glass has the same density as the water in a bathtub or swimming  pool . All substances have characteristic densities, which does not depend on how much of a substance you have.
    ::密度描述物质在一定空间中的数量。 将更多物质包装在特定空间中的物质密度较高。 饮用水杯中的水密度与浴缸或游泳池中的水密度相同。 所有物质都具有特性密度, 这不取决于您有多少物质。

    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. Density can be calculated using the following equation:
    ::质量是测量一个物体中物质数量的一个尺度。一个物体接收的空间物体数量用其体积来描述。一个物体的密度取决于其质量和体积。密度可以用下列方程式计算:

    Density=Mass/Volume

    Samples that are the same size but have different densities, will have different masses. Gold has a density of about 19 g/cm 3 . Pyrite has a density of only about 5 g/cm 3 . Quartz is even less dense than pyrite and has a density of 2.7 g/cm 3 . If you picked up a piece of pyrite and a piece of quartz that were the same size, the pyrite would seem almost twice as heavy as the quartz.
    ::相同大小但密度不同的样本将具有不同的质量。金的密度约为19克/立方厘米。金的密度约为19克/立方厘米。金的密度仅为5克/立方厘米。 夸尔茨的密度甚至比锡的密度更低,密度为2.7克/立方厘米。 如果你捡到一块相同大小的锡石和一块石英,那么金石的密度将几乎比石英重两倍。

    Specific gravity  is used to identify minerals.  Specific gravity  measures how heavy the mineral is relative to the same volume of water.
    ::具体重力用于鉴定矿物,具体重力测量矿物相对于相同水量的重量。

    Hardness
    ::硬硬度

    Hardness  is a mineral’s ability to resist being scratched. Minerals that are not easily scratched are hard. You test the hardness of a mineral by scratching its surface with a mineral of a known hardness. Mineralogists use the Mohs Hardness Scale ( Table   ), as a reference for mineral hardness. The scale lists common minerals in order of their relative hardness. You can use the minerals in the scale to test the hardness of an unknown mineral.
    ::硬度是矿物抵抗被刮伤的能力。 不容易刮伤的矿物很难。 您通过用已知硬度的矿物刮擦矿物表面来检验矿物的硬性。 矿物学家用莫赫斯硬度表(表)作为矿物硬度的参考。 比例表列出了普通矿物的相对硬度。 您可以使用规模中的矿物来测试未知矿物的硬性。

    Mohs Hardness Scale
    ::Mohs 硬度缩放

    As you can see, diamond is a 10 on the Mohs Hardness Scale. Diamond is the hardest mineral; no other mineral can scratch a diamond. Quartz is a 7. It can be scratched by topaz, corundum, and diamond. Quartz will scratch minerals that have a lower number on the scale, such as fluorite, which has a hardness of 4. Suppose you had a piece of pure gold. You find that calcite scratches the gold. Gypsum does not. Gypsum has a hardness of 2 and calcite is a 3. That means the hardness of gold is between gypsum and calcite. So the hardness of gold is about 2.5 on the scale. A hardness of 2.5 means that gold is a relatively soft mineral. It is only about as hard as your fingernail.
    ::正如你所看到的,钻石在Mohs Hardness 比例上是10。钻石是最硬的矿物质,其他矿物质都无法抓取钻石。Quartz是7。Quartz是7。它可以被表层、圆丘和钻石抓取。Quartz将抓取规模小于2.5的矿物,如花粉,4级硬度为4级。假设你有一块纯金。你会发现石化石抓取黄金。Gypsum没有。Gypsum的硬度为2级,石化石是3级。这意味着金的硬度在石膏和石化之间。因此金的硬度在2.5级上是2.5级。2.5级硬度意味着金是一个相对柔软的矿物。它和你的手指一样硬。

    Hardness Mineral
    1 Talc
    2 Gypsum
    3 Calcite
    4 Fluorite
    5 Apatite
    6 Orthoclase feldspar
    7 Quartz
    8 Topaz
    9 Corundum
    10 Diamond

    Cleavage and Fracture
    ::裂裂和断裂

    Different types of minerals break apart in their own way. Remember that all minerals are crystals. This means that the atoms in a mineral are arranged in a repeating pattern. This pattern determines how a mineral will break. When you break a mineral, you break  chemical bonds . Because of the way the atoms are arranged, some bonds are weaker than other bonds. A mineral is more likely to break where the bonds between the atoms are weaker.
    ::不同种类的矿物以自己的方式破裂。 记住所有矿物都是晶体。 这意味着矿物中的原子都是以重复的方式排列的。 这个模式决定了矿物如何破裂。 当你打破矿物时, 你打破化学债券。 由于原子的排列方式, 有些债券比其他债券弱。 当原子之间的债券较弱时, 矿物更有可能破裂 。

    Cleavage
    ::解裂

    Cleavage  is the tendency of a mineral to break along certain planes. When a mineral breaks along a plane, it makes a smooth surface. Minerals with different crystal structures will break or cleave in different ways ( Figure   ). Halite tends to form cubes with smooth surfaces. Mica tends to form sheets. Fluorite can form octahedrons.
    ::裂缝是一种矿物沿着某些平面碎裂的趋势。 当矿物沿着一架飞机碎裂时, 它会形成光滑的表面。 具有不同晶体结构的矿物会以不同的方式破裂或断裂( 图 ) 。 Halite 倾向于形成有光滑表面的立方体。 Mica 倾向于形成圆板。 Fluorite 可以形成八面体 。

    Examples of mineral cleavage: A. Halite, B. Muscovite, C. Fluorite with different shapes.
     
    Minerals with different crystal structures have a tendency to break along certain planes. (A) Halite breaks into cubes. (B) Muscovite breaks into sheets. (C) Fluorite breaks into octagons.

    Minerals can form various shapes. Polygons are pictured below ( Figure   ). The shapes form as the minerals are broken along their cleavage planes. Cleavage planes determine how the crystals can be cut to make smooth surfaces. People who cut  gemstones  follow cleavage planes. Diamonds and emeralds can be cut to make beautiful gemstones.
    ::矿物可以形成不同的形状。 多边形图示(图示 ) 。 矿物质在它们的三角平面上断裂时的形状会形成。 裂纹平面的平面决定如何切割晶体以制造光滑的表面。 切割宝石的人会跟随碎石平面。 钻石和宝石可以切割成美丽的宝石。

    Three polyhedral shapes: A) cube, B) parallelepiped, C) octahedron, demonstrating crystal structures.
     
    (A) Cubes have six sides that are all the same size square. All of the angles in a cube are equal to 90°. (B) Rhombohedra also have six sides, but the sides are diamond-shaped. (C) Octahedra have eight sides that are all shaped like triangles.

    Fracture
    ::断裂

    Fracture  describes how a mineral breaks without any pattern. A fracture is uneven. The surface is not smooth and flat. You can learn about a mineral from the way it fractures. If a mineral splinters like wood, it may be fibrous. Some minerals, such as quartz, fracture to form smooth, curved surfaces. Pictured below is a mineral that broke forming a smooth, curved surface ( Figure   ).
    ::断裂描述矿物如何无任何模式地断裂。 断裂是不均衡的。 表面不平滑, 平坦。 您可以从断裂的方式中了解矿物质。 如果矿物质像木质一样碎裂, 它可能是纤维化的。 一些矿物质, 如石英, 碎裂会形成平滑的弯曲表面。 下面的图画是一个断裂的矿物质, 形成平滑、 弯曲的表面( 图示 ) 。

    A black mineral with a smooth, curved surface from a fracture.
     
    This mineral formed a smooth, curved surface when it fractured.

    Other Identifying Characteristics
    ::其他识别特征

    Minerals have other properties that can be used for identification. For example, a mineral’s shape may indicate its crystal structure. Sometimes crystals are too small to see. Then a  mineralogist  may use a special instrument to find the crystal structure.
    ::矿物有其他特性可以用来识别。 比如,矿物的形状可以表明其晶体结构。 有时晶体太小,看不见。 矿工可以使用特殊仪器寻找晶体结构。

    Some minerals have unique properties. These can be used to the minerals. Listed below are some of these properties ( Table   ); an example of a mineral that has each property is also listed.
    ::有些矿物具有独特的特性,可用于矿物,下面列出其中一些特性(表);还列出了拥有每种特性的矿物的例子。

    Property Description Example of Mineral
    Fluorescence Mineral glows under  ultraviolet light Fluorite
    Magnetism Mineral is attracted to a magnet Magnetite
    Radioactivity Mineral gives off radiation that can be measured with Geiger counter Uraninite
    Reactivity Bubbles form when mineral is exposed to a weak acid Calcite
    Smell Some minerals have a distinctive smell Sulfur (smells like rotten eggs)

    Summary
    ::摘要

    • Some minerals have a unique property that makes them fairly easy to identify. But many do not.
      ::有些矿物具有独特的特性,因此很容易识别,但许多矿物没有。
    • Different minerals can be identified by different properties.
      ::不同的矿物质可按不同的特性加以识别。
    • Cleavage can be a unique and beautiful indicator of mineral type.
      ::清除可成为矿物类型的一个独特和美丽的标志。

    Review
    ::回顾

    1. How does streak differ from color?
      ::连字符串与颜色有何不同?
    1. How does cleavage differ from fracture?
      ::裂缝和骨折有什么区别?
    1. List a few minerals and the property that makes each of them unique; e.g. magnetite is magnetic.
      ::列出少数矿物及其独特性的财产,例如磁铁是磁铁。

    Explore More
    ::探索更多

    Use the resource below to answer the questions that follow.
    ::利用以下资源回答以下问题。

     

     

    1. What color streak would pyrite leave on sandpaper?
      ::在砂纸上留下什么颜色?
    1. What color streak would real gold leave on sandpaper?
      ::真正的黄金在砂纸上留下什么颜色?
    1. List some examples of the different types of quartz.
      ::列举不同类型石英的一些例子。
    1. What characteristic do all types of quartz share?
      ::所有种类的石英都具有什么特征?
    1. What is unique about mica?
      ::米卡有什么独特之处?
    1. What is mica used for?
      ::MICA是用来做什么的?
    1. What was azurite used for in ancient times?
      ::古代的阿祖瑞特是用来做什么的?
    1. In what colors can calcite be found?
      ::计算出什么颜色?
    1. What color does green calcite streak? Is this true for all colors of calcite?
      ::绿色石墨的颜色是什么? 这是所有石墨颜色的颜色都一样吗 ?
    1. What is galena?
      ::什么是加莱娜?
    1. How can you tell that fluorite is not a calcite mineral?
      ::你怎么能分辨出 氟化物不是钙矿物质呢?
    1. How many sides does garnet have?
      ::盖网有多少边?