1. 2006 Prentice Hall Science Explorer: Earth Science
Property of Minerals
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2006 Prentice Hall Science Explorer: Earth Science

2. What is a Mineral?
Mineral- A mineral is a naturally occurring, inorganic solid that has a crystal structure and a definite chemical composition.
All five of these characteristics must be present for a substance to be classified as a mineral.
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3. What does this mineral definition mean?
A mineral is a NATURALLY OCCCURING, INORGANIC SOLID that has a CRYSTAL STRUCTURE and a DEFINITE CHEMICAL COMPOSITION.
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4. Solid- has a definite volume and definite shape.
Naturally occurring- substance formed by processes in the natural world, not man made.
Inorganic-non-carbon bearing material; not made of or from living organisms or once living organisms.
Solid- has a definite volume and definite shape.
Crystal Structure- the particles of a mineral line up in a pattern that repeats over and over again. The repeating pattern of a mineral’s particles form a solid called a crystal.
Definite Chemical Composition- always contains certain elements in definite proportions.
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5. Mineral Identification
Each mineral has characteristic properties that can be used to identify it.
Color
Streak
Luster
Cleavage and Fracture
Hardness
Crystal Systems
Density
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6. Mineral Characteristics
Color- the color of the mineral
Streak-the color of the mineral in powder form; observed by rubbing the mineral against an unglazed porcelain or ceramic tile (streak≠color)
Luster-the light that is reflected from a minerals surface
Metallic-highly reflective, shiny (like polished metal)
Nonmetallic-dull, non reflective material
Cleavage-the tendency of a mineral to break/split along specific planes of weakness to form smooth, flat surfaces; often expressed as an angle degree
Fracture-minerals that break in inconsistent patterns, forming irregular, uneven pieces with curved or jagged edges
The color of a mineral is an easily observed physical property. But the color of a mineral alone often provides too little information to make an identification.
Color can be used to identify only those few minerals that always have their own characteristic color.
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7. Color, Luster, Cleavage and Fracture
Quartz comes in a variety of colors
Metallic and Dull Luster
New holt fig 1, 2 pg 109 and 110
Old Holt fig 9-6 and 9-7 pg 164 and 165
Fracture
Examples of mineral cleavage
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8. More Mineral Characteristics
In 1812, Friedrich Mohs, invented a test to describe the hardness of minerals, Mohs Hardness Scale. This scale ranks 10 minerals from softest to hardest.
Hardness-the measure of the ability of a mineral to resist surface scratches; independent of fracture or cleavage
Hardness can be determined by a scratch test. A mineral can scratch any mineral that is softer than itself.
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9. Old Holt, Table 9-2, pg 165
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10. Density
Density-the ratio of the mass of a substance to its volume; specific to mineral type
Each mineral has a characteristic density.
Density = mass
volume
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11. Definite Crystalline Structure
At times and fairly rare, a mineral will form in an open space and grow into one large crystal, possibly taking the shape of one of the six major crystal systems.
Monoclinic
Cubic
Hexagonal
Tetragonal
Orthorhombic
Triclinic
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12. Special Mineral Properties
Fluorescence-minerals that “glow” under ultraviolet light
Phosphorescence-rocks that continue to “glow” even after an ultraviolet light is removed
Magnetism-some minerals are magnetic
New holt, fig 4, pg 113
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13. More Special Properties
Refraction-transparent minerals that bend light as it passes through the mineral creating a view “through” the mineral
Double refraction-two images produced
Radioactivity-minerals whose atoms are unstable; release high energy particles
New holt, fig 5 pg 114
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