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Minerals. Definition: A mineral is. naturally occurring Made by Mother Nature -it is NOT man made!. An inorganic material (It is NOT and has NEVER been living). It is NOT a liquid It is NOT a gas. It is a SOLID. It has a crystalline structure when examined under a microscope.
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Definition: A mineral is • naturally occurring Made by Mother Nature -it is NOT man made!
An inorganic material (It is NOT and has NEVER been living)
It is NOT a liquidIt is NOT a gas It is a SOLID
It has a crystalline structure when examined under a microscope It has either a • cubic • hexagonal • orthorhombic • monoclinic • triclinic or • tetragonal Crystalline Structure
It has a definite chemical composition • Every atom of the mineral has the same chemical formula • For example: Halite: NaCl Galena: PbS Fluorite: CaF2 Talc: Mg3Si4O10(OH)2
naturally occurring inorganic solid crystalline structure chemical composition Now I See Crystal Clear. A mineral is:
Classification of minerals HARDNESS • Geologists use the Mohs Hardness Scale to determine a mineral’s hardness. • The Mohs Hardness Scale ranks a mineral’s hardness from 1-10 with 1 being the softest ( can scratch it with your fingernail) and 10 being the hardest (cannot be scratched by any other substance). • The mineral with a Mohs Hardness Scale of 1 is talc. • The mineral with a Mohs Hardness Scale of 10 is diamond.
Color • Color is a physical property of a mineral. • It is NOT a dependable way to classify minerals because many minerals may have the same color. Examples: • Gold and pyrite are both gold. • Quartz may be rosy pink, white, purple, gray or yellowy.
Streak • A mineral’s streak is the color it leaves behind when scratched on an unglazed tile called a streak plate. • A mineral’s streak is the color of its powder.
Luster • A mineral’s luster describes how the mineral reflects light. Examples: • Minerals that are metals are shiny. • Quartz has a glassy luster. • Talc has a greasy luster.
Density • Each mineral has its own characteristic density. That is why density is an excellent way to identify a mineral. • Density refers to a mineral’s mass per unit of volume. • Geologists use a balance to determine a mineral’s mass and water displacement with a graduated cylinder to determine its volume. • Density is expressed in units called grams per cubic centimeter. • The formula for calculating the density of a mineral (or any substance) is its mass divided by its volume.
Cleavage and Fracture • Cleavage refers to a mineral’s ability to split along flat surfaces. (String cheese has cleavage along a regular surface.) • Fracture refers to a mineral’s ability to break along irregular surfaces. (Tearing a piece of paper is an example of what this looks like.)
Special Properties • Some minerals have magnetic properties. That means that they are attracted to magnets. • Some minerals are fluorescent. That means that they glow under ultra violet (UV) light. • Some minerals are radioactive. They cause a Geiger counter to be set off. • Other minerals have electrical properties. Quartz produces a slight electrical current when pressure is applied to it.