Mineral Identification Mr. Jensen Ref: McGuire – ES/PS 1. The Earth provides us with materials important to our lives.        a) List Earth materials we use in natural, purified or processed form, including ingredients in other materials        b) explain the need to conserve our resources.

Identifying Minerals Minerals can be identified using their distinctive physical and chemical properties. Mineral properties include: _______________    3. Minerals can be identified on the basis of well-defined physical and chemical properties.        a) mineral properties include color, crystal form, cleavage, hardness, density, luster and streak.        b) while color is a readily observed property, some minerals show a great range of colors.

Table 2-1: Common Rock Forming Minerals

Yoav Levy/Phototake NYC Minerals: Color Color Many minerals have a characteristic color _______________ may discolor certain light colored minerals Ex. Quartz and calcite which are typically colorless. Dark color minerals typically do not have this problem. Minerals and Mineralogy Minerals come in a wide variety of colors and structures, including such diverse members as glassy black obsidian; jewel-toned jasper; clear, hard diamonds; and soft, chalky talc. Defined as naturally occurring or naturally formed inorganic substances neither animal or vegetable, minerals are the source of valuable metals, most frequently mined in the form of ore. Living organisms need minerals to maintain proper nutrition—without them, disease and even death may result. Mineralogists classify minerals on the basis of their chemical composition, crystal class, hardness, and appearance (color, luster, opacity). Here, a selection of minerals demonstrates some of the visible differences by which they can be identified. Yoav Levy/Phototake NYC "Minerals and Mineralogy," Microsoft® Encarta® 98 Encyclopedia. © 1993-1997 Microsoft Corporation. All rights reserved. Color the most easily observed property, but usually the least useful.

Minerals: Luster Luster Describes the way light is ____________ from the freshly cut surface of a mineral. _______________ Luster Hard shiny look like polished metal. Light is unable to penetrate. Ex. Pyrite, galena and magnetite May be shiny but some light is able to penetrate. Includes glassy, waxy, pearly and earthy (dull) lusters Ex. Calcite, quartz and feldspar Have examples ready to demo. May want to add slide with photo’s.

Minerals: Streak Streak The color of the mineral in a _______________ form. The test for streak is performed by rubbing a fresh corner of the mineral across a white, unglazed __________ __________. Several minerals have a streak that is not the same color as the mineral itself. Most metallic luster minerals have a dark colored streak. (Ex. Graphite, Pyrite) Have a streak plate to demo.

Minerals: Crystal Structure Minerals form characteristically ____________ crystals A crystal is a regularly shaped solid formed by an __________ __________ of atoms.

Minerals: Hardness Hardness Minerals differ in hardness Tested by _______________ mineral with other materials of known hardness Friedrich _______ (Geologist) created the _______ scale for hardness

Minerals: Cleavage Cleavage If a mineral breaks readily along ______ _________ it shows cleavage Many minerals break along ______ _________ called cleavage planes Minerals that break along even surfaces that do not follow atomic arrangement (crystal faces) are said to show ______________

Minerals: Density Density Minerals vary in density and __________ __________ (ratio of density and water) Example of specific gravity. Density -= 4 g/cm3 ; water = 1 g/cm3 = specific gravity of 4.