Personal Information:  My name is Kay Cartledge.  I teach a self-cotained learning disability class
at North Augusta Elementary.  I presently have ten male students in my class.

Unit Overview:  My unit will be on the varied earth materials that have different physical properties and uses, which will include rocks, minerals, water, and soil.  Using the South Carolina State Science Standards for third grade, my students will increase their knowledge of earth science using various earth materials and activities.  My students will complete science experiments using the scientific method and expand their knowledge of the physical properties of our land.
Lesson Title:  Our World of Minerals
Lesson Objective:  The learner will be able to define the word mineral.
                                 The learner will be able to give examples of minerals and their uses.
                                 The learner will be able to state the four main characteristics of minerals.




What is a Mineral?
An object that has never been alive, was formed in nature, and the atoms are arranged in a regular pattern, which form solid units called crystals, is said to be a mineral.  A mineral has the same chemical makeup wherever it is found.  In higher grades, a mineral is usually defined as a naturally occurring solid substance consisting of a single element or compound.  There are no two minerals that are exactly the same.  Minerals have different properties and different uses.  Minerals are formed in soil and are also found on the moon, Mercury, Venus, and Mars.

A mineralogists is a scientist who studies minerals.  Minerals are usually a compound of two or more elements.  Some minerals such as gold and sulfur are made of only one element.  The common elements that form minerals are oxygen and silicon.  Other elements include aluminum, iron, calcium, sodium, potassium, and magnesium.  Our land and our oceans rest on a bed of rock made of minerals.  Rocks found on the earth's surface are said to contain minerals.  There are about 2000 kinds of minerals, but only 100 are said to be common minerals.




Minerals are dug from the earth, and man makes many products using minerals.  He uses minerals to make cement and steel, which are used to build buildings.  Minerals are used to make fertilizers for farming, chemicals for manufacturing, and many other products. Graphite is a common mineral that is used in making "lead" pencils, and rare minerals such as gold and silver are used for jewelry and money.  Many people think that any substance that is taken from the earth is a mineral.  Coal, petroleum, natural gas, and sand are taken from the earth, but they are not minerals.  Many foods and water contain substances like calcium, iron, and phosphorus.  Mineralogists do not consider any of these to be minerals.  Minerals will differ greatly in appearance and the way they feel.  Some minerals may have glass-like surfaces and sparkle when the light shines on them.  Other minerals may be dull and greasy.  Some minerals are hard enough to cut glass, while others are soft enough to scratch with your fingernail.




Minerals are said to have four main characteristics:  (1) luster, (2) cleavage, (3) hardness, and (4) color.
Luster of a mineral may be metallic or nonmetallic.  Minerals that shine like a metal are said to be metallic. Some examples of metallic minerals include galena, gold, and ilmenite.  Minerals with nonmetallic luster will often vary in appearance.  For example, tale has a surface that resembles pearls, while quartz looks glassy and shiny.
Cleavage occurs when a mineral is split into pieces that have flat surfaces.  Minerals split differently.  Some minerals only split in one direction, while others split in several directions.  Another difference is the angles in which the flat surfaces meet.  For example, Halite has three cleavage directions, and when it breaks, it separates into small cubes.  A pyramid is formed as a diamond may split in four directions.
Hardness is tested in minerals by scratching one mineral with another.  Mineralogists use a scale, Mohs Hardness Scale, to determine the hardness of a given mineral.  One mineral is scratched with another mineral, and the harder mineral scratches the softer mineral.  A German mineralogist, Friedrich Mohs, invented the scale in 1822.  A list of ten minerals are numbered one to ten, from the softest to the hardest.  The hardness of other minerals is determined by whether they scratch, or are scratched, by the minerals in the Mohs Scale.
Color in some minerals is determined by the make up of the crystals.  The red of cinnabar, the black of ilmenite, and the green of serpentine all result from the chemical make up of these minerals.  In other minerals, color may be determined from the chemical impurities.





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(January, 2002)
"The views expressed here are not necessarily those of the University of South Carolina."