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Hall of Minerals Hall of Gems Educator’s Guide Harry Frank Guggenheim Hall of Minerals Morgan Memorial Hall of Gems Inside: • Suggestions to Help You Come Prepared • Essential Questions for Student Inquiry • Strategies for Teaching in the Hall • Map of the Exhibition • Online Resources • Correlation to Standards • Glossary amnh.org/mineralsgems/educators ESSENTIAL Questions What is a mineral? • Hardness is the degree of resistance to being scratched. It’s determined by rubbing substances of known A mineral is a naturally hardness against minerals and calibrating the results occurring crystalline solid. on the Mohs Scale. Diamond, the hardest mineral, is Crystals are orderly 10 on the scale, while quartz is 7 and talc is 1. arrangements of atoms. Minerals are the building • Fracture and cleavage describe the way minerals break blocks of rocks, which apart. Fracture is the tendency to break along rough make up most of the planet. or curved surfaces, while cleavage is the tendency to Some minerals, like gold break along planes of weakness. Cleavage can help and silver, consist of identify crystal symmetry, which can be useful in telling essentially just one similar-looking minerals apart. element, while others combine two or more. The properties of minerals determine how we can use quartz (Si0 ) Minerals are classified by 2 them. For example, diamond and corundum (ruby) are their chemical compositions, which are defined by used as abrasives because they’re very hard, while soft formulas and by the way the atoms of those chemical and slippery graphite and molybdenite can be lubricants. elements are arranged into crystals. For example, Si02 is the formula for quartz, in which atoms of silicon and How do minerals form? oxygen are arranged in a precise geometry. Gems are Minerals form when minerals that are beautiful, rare, and durable, and which elements crystallize and/ have been cut and/or polished to enhance their beauty. or react chemically with each other in response to What are the properties of minerals? environmental conditions The physical properties of minerals are determined such as changing pres- by their chemical composition and crystal structure. sure and temperature. Scientists magnify, crush, illuminate, scratch, and break They grow by adding jadeite (NaAlSi O ) specimens in order to determine these properties. layers to a starting point 2 6 or surface, and well-formed • Luster is the way a mineral’s surface interacts with crystals most commonly grow in an open space in the light — how brilliant or dull it appears, for example. presence of a fluid. Minerals form everywhere on Earth — Lusters are either metallic (like pyrite) or non-metallic from thousands of meters deep to its surface and (examples include talc, which is pearly; quartz, which is atmosphere — over time frames ranging from seconds glassy; and sulfur, which is earthy). Some minerals (like to millions of years. The conditions under which they graphite) fall in between and are called submetallic. formed tell geologists important things about the planet. For example, jadeite jade probably formed at high pressure where oceanic crust was pushed beneath continental crust, while many rubies were forged where continents collided to create mountain chains. Why are minerals important? Studying rocks and minerals helps us understand the metallic: non-metallic: submetallic: greater physical world, including Earth’s history and pyrite (FeS2) talc (Mg3Si4O10(OH)2) graphite (C) dynamics. By analyzing a rock’s mineral content and • Scientists crush a mineral by swiping it across a ceramic texture, scientists can learn about the conditions at “streak plate” to reveal the color of its powder — its which it formed. Earth materials are resources. We rely streak. This can help distinguish between minerals with on minerals found in Earth for many products, including the same color but different streak, like hematite metals, ceramics, fillers, semiconductors, glass, and and magnetite. fertilizer. Minerals are also a source of nutrients that all living things require. GLOSSARY COME PREPARED crystal: a naturally occurring, Plan your visit. For information about reserva- symmetrical solid with flat tions, transportation, and lunchrooms, visit surfaces, like a cube, a prism, amnh.org/plan-your-visit. or even a snowflake. Crystals Read the Essential Questions in this guide to are made of atoms arranged in barite (BaSO ) see how the themes in these two halls connect to an orderly, repeating pattern. 4 your curriculum. Identify the key points that you’d deposit: an accumulation or concentration of minerals like your students to learn. laid down by a natural process, such as gravity or the Review the Teaching in the Hall sections of this movement of water, wind, or ice guide for an advance look at the specimens that you and your class will be encountering. element (chemical element): matter composed of a single type of atom. Few elements are found in an Download activities and student worksheets uncompounded, pure form. The periodic table is the at amnh.org/mineralsgems/educators. Designed classification of the chemical elements. for use before, during, and after your visit, these activities focus on themes that correlate to the gem: a mineral that standards. has been cut and/or Decide how your students will explore the halls. polished to enhance diamond (C) its beauty • You and your chaperones can facilitate the visit using the Teaching in the Hall sections. magma: molten rock (formed below Earth’s surface). Magma that reaches the surface is called lava. • Students can use the student worksheets to explore the halls on their own or in small groups. mineral: a natural solid with a crystal structure and a • Students, individually or in groups, can use specific chemical composition copies of the map to choose their own paths. mineralogy: the study of minerals, or what mineralogists — including crystallographers, mineral physicists, and crystal chemists — do CORRELATIONS TO THE NEXT GENERATION Mohs Scale of Hardness: a system for determining the resistance of a mineral to being scratched, with 1 being SCIENCE STANDARDS the softest (talc) and 10 the hardest (diamond) Science Practices • Asking questions • Developing and using models • Planning and carrying out rock: a naturally occurring solid made of one or more investigations • Analyzing and interpreting data minerals. Rocks make up most of Earth’s crust. • Using mathematics and computational thinking • Constructing explanations • Engaging in argument sediments: small fragments of mineral or rock that are from evidence • Obtaining, evaluating, and broken off, carried, and deposited by wind, water, or ice communicating information vein: a distinct body of Crosscutting Concepts • Patterns • Cause and effect: crystallized minerals that mechanism and explanation • Scale, proportion, and occupies a fissure quantity • Systems and system models • Energy and matter: flows, cycles, and conservation • Structure within a rock mass and function • Stability and change Disciplinary Core Ideas • PS1.A: Structure and Properties of Matter • PS1.B: Chemical Reactions • ESS2.A: Earth Materials and Systems • ESS2.B: Plate gold and quartz vein Tectonics and Large-Scale System Interactions in metamorphic rock • ESS3.A: Natural Resources HARRY FRANK GUGGENHEIM HALL OF MINERALS Teaching in the HALL This hall presents hundreds of striking specimens collected from around the world. Almost everything on display came out of Earth looking the way it does here. The guided explorations below are designed around two sections of the hall: Properties of Minerals and Mineral Forming Environment. The numbers correspond to stops on the map. PROPERTIES OF MINERALS Scientists perform a range of measurements to determine the crystal structure of minerals, as well as their physical, chemical, and optical properties. Some minerals are easy to identify, but most require multiple tests. In this section, students will explore four cases to see how mineral properties can be determined and measured. 1a. Atoms, space lattices, and crystals: A mineral’s 1d. Optical properties of minerals: Color is an important characteristic crystal structure is determined by how its optical characteristic, but can vary within mineral types atoms fit together. Have students compare the models and overlap across others. Streak — the color of the in the center of the case to the crystal shapes of mineral residue left when the mineral is scraped against a rough specimens to the right. Ask them to explore how atomic surface — can help distinguish minerals from one another. arrangements in different minerals are expressed in Draw students’ attention to hematite (#48). Like many actual crystals, and how bonded groups repeat in three minerals, it is black, but its streak is distinctly red. Pyrite dimensions to make crystals. (#44) is gold, but its streak is black. 1b. Physical properties of minerals: These different crystal structures result in a huge variety of physical properties — even when minerals are made of the same element or elements. Have diamond students compare two carbon-based minerals, diamond and graphite. How do their crystal structures and physical properties differ? (In diamonds, atoms are closely packed in all directions, making it very hard. Graphite’s atoms graphite are closely packed along one plane streak plates show the colors of various mineral powders (#42-51) only, which makes it softer.) Have students explore a variety of characteristic properties (hardness, cleavage, Luster is another optical property.
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