An Introduction A mineral is a naturally occurring

�A mineral is a naturally occurring, inorganic solid with an orderly crystalline structure and

�Crystallization from magma: crystals form as the temperature drops below their melting points; iron,

� Precipitation: �Common minerals are dissolved in water minerals: Halite (Na. Cl), which we

� Pressure and temperature: some minerals form when preexisting minerals/rocks are subjected to high

� Hydrothermal solutions: high temperature solutions (100 -300 C) flowing through existing minerals/rocks, dissolve

� There are over 3800 named, indentified minerals, and they are broken into groups;

� Each mineral has its own unique set of characteristics. � Color � Streak:

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An Introduction

�A mineral is a naturally occurring, inorganic solid with an orderly crystalline structure and a definite chemical composition. � Yes, this means that coal is not a mineral.

�Crystallization from magma: crystals form as the temperature drops below their melting points; iron, calcium, magnesium minerals solidify first, sodium, potassium, and aluminum at lower MP. �Examples: �Feldspar (used for ceramics) �Quartz (used for glass manufacture) �Muscovite (common white Mica) �Hornblende

� Precipitation: �Common minerals are dissolved in water minerals: Halite (Na. Cl), which we know as salt Gypsum (Ca. SO 4· 2 H 2 O) Calcite (Ca. CO 3)

� Pressure and temperature: some minerals form when preexisting minerals/rocks are subjected to high temperatures and pressures. � Examples: �Garnets �Chlorite in schist

� Hydrothermal solutions: high temperature solutions (100 -300 C) flowing through existing minerals/rocks, dissolve and reform into new minerals. � Examples: �Quartz (Si. O 2) �Pyrite (Fe. S 2)

� There are over 3800 named, indentified minerals, and they are broken into groups; here are some of them: � Silicates: minerals with a framework of silicon and oxygen; they are the most numerous group. � Carbonates: very common; usually a salt of a metal and the carbonate ion: CO 3 -2. � Oxides: usually metals that have reacted with oxygen � Sulfates and sulfides: metals that reacted with sulfur, some further reacted with oxygen/water/solutions � Halides: minerals where metals have reacted with halogens (group 7 A) � Native elements: some elements that are found without having reacted with another element: Gold, Silver, Copper, Sulfur, Carbon (diamond, graphite)

� Each mineral has its own unique set of characteristics. � Color � Streak: color in a powdered form or when rubbed against an unglazed white tile � Luster: reflection/sheen � Crystal form: showing the internal crystal lattice in an external form � Hardness: a relative scale: Mohs � Cleavage: tendency to break along flat surfaces � Fracture: when mineral do not cleave, the type of broken surface that does occur. � Density/specific gravity: ratio of a mineral/substance’s mass to its volume. � Others: feel (talc: greasy)