ROCKS & MINERALS

Properties of Minerals

mineral – naturally occurring, inorganic solid that has a crystal structure and a definite chemical composition

Minerals must have the following FIVE characteristics: 1. Must be formed by processes that occur in the natural world 2. Must be inorganic, meaning that it cannot come from materials that were once part of a living thing 3. A solid – with definite shape and definite volume 4. Particles that make it up line up in a repeating pattern which form a crystal 5. Has a definite chemical composition or range of compositions

Each mineral has certain characteristics that help identify it: Color – used to identify a few minerals that have their own characteristic coloring Streak – color of a mineral’s powder Luster – how light is reflected from a mineral’s surface Density – each mineral has a characteristic density (d=m/v) Cleavage – if a mineral breaks easily along flat surfaces Fracture – when a mineral breaks apart in an irregular way

Mineral characteristics cont. Hardness – using the Mohs hardness scale, this scale ranks ten minerals from softest to hardest Crystal system – crystals grow atom by atom to form a particular structure – these structures are grouped into six different categories based on the number and angle of the crystal faces

Special properties can also be used such as magnetism and ability to glow under an ultraviolet light.

Mineral Formation & Resources

Geode rounded, hollow rock that is often lined with mineral crystals

Crystallization process by which atoms are arranged to form a material with a crystal structure

Minerals can form two ways: 1. Crystallization of magma and lava – minerals form as hot magma cools inside the crust, or as lava hardens on the surface. When these liquids cool to a solid state, they form crystals. 2. Crystallization of materials dissolved in water – when elements and compounds that are dissolved in water leave a solution (mixture in which one substance in dissolved in another), crystallization occurs.

quartz vein, prominent from the surrounding weathered rock Some minerals form when pure metals that crystallize from hot water solutions underground often form veins, or a narrow channel or slab mineral that is different from the surrounding rock quartz vein, prominent from the surrounding weathered rock

Minerals are the source of a variety of materials used to make many products. gemstone – hard, colorful mineral that has a brilliant or glassy luster; once cut and polished it is called a gem metals – minerals are the source of metals such as aluminum, iron, copper or silver ore – a rock that contains a metal or other useful mineral that can be mined and sold at profit

To produce metal from a mineral: 1. Rocks containing minerals must be located through prospecting 2. Ore deposits are removed from ground through mining 3. Rock is processed by smelting to produce metals A worker operates a manufacture mixer with fused aluminum at the foundry shop of aluminum smelter plant in the Siberian city of Krasnoyarsk February 3, 2010. REUTERS/ILYA NAYMUSHIN/FILES

Classifying Rocks

Geologists look at the mineral composition, color and texture of a rock, which can contain a mixture of minerals and other materials or only a single mineral.

Color – provides clues to the rock’s mineral composition granite – light colored rock having high silica content basalt – dark colored rock that is low in silica Texture – the look and feel of the rock’s surface which is made up of particles of minerals or other fine rocks called grains Grain size Grain shape Grain pattern

Geologists classify rocks into three major rock groups based on how they form: Igneous Sedimentary Metamorphic

Igneous Rock created when magma or lava cools and crystallizes

Sedimentary Rock rock material that forms where rocks are broken down into smaller pieces or dissolved in water as rocks erode or the remains of plants and animals are pressed and cemented together

Metamorphic Rock forms when existing rock is changed by heat, pressure or chemical reactions

Rock Cycle series of processes that change one type of rock into another type of rock

Rock Groups

IGNEOUS ROCKS Formation: May form on or beneath Earth’s surface. Extrusive rocks – igneous rocks formed from lava that erupted onto Earth’s surface Intrusive rocks – rock that formed when magma hardened beneath Earth’s surface

IGNEOUS ROCKS Texture: Geologists determine whether an igneous rock is extrusive or intrusive based on its texture extrusive - small, hard to see crystals intrusive -large and interlocking crystals Composition: can sometimes be determined by color of rock

SEDIMENTARY ROCKS sediment – small, solid pieces of material that come from rocks or remains of living things Formed through a series of processes which include: erosion – form sediment by particles getting carried away from their source by wind and water deposition – process by which sediment settles out of the water or wind carrying it compaction – process that presses sediment together growing thick layers that build up over millions of years cementation – process in which dissolved minerals crystallize and glue particles of sediment together

METAMORPHIC ROCKS Heat and pressure deep beneath Earth’s surface can change any rock into metamorphic rock. foliated – metamorphic rocks that have their grains arranged in parallel layers or bands nonfoliated – mineral grains are arranged randomly

Copyright Information ©2015 Erica L Colón: Nitty Gritty Science, LLC. All rights reserved by the author. My terms for use for all products available are as follows: Purchase of this unit entitles the purchaser the right to reproduce the pages in limited quantities for classroom use only. Duplication for an entire school, an entire school system, or commercial purposes is strictly forbidden without written permission from the author: Erica Colón: NittyGrittyScience@gmail.com or by purchasing multiple licenses. Copying any part of this product and placing it on the internet in any form (even a personal/classroom website) is strictly forbidden and is a violation of the Digital Millennium Copyright Act (DMCA). You may post pictures from using this product in your classroom as long as you provide a link back to my store.