Transcript Mineral Introduction

Mineral Introduction
Chapter 3
Minerals
• A mineral is a naturally occurring, inorganic
solid, with a definite chemical composition
and orderly arrangement of atoms!
• All minerals are formed by natural processes on
or inside Earth, with no input from humans.
• Minerals are crystalline solids which menas that
they have a definite compositon and structure.
• Crystalline menas that the atoms are arragned
in a pattern that is repeated over and over again.
Crystals
• A crystal is a solid in which the atoms are
arranged in orderly, repeating patterns.
• A crystal system is a group of crystals that have
similar atomic arrangements and therefore
similar external crystal shapes.
• There are six major crystal systems, which
classify minerals according to their crystal
structures.
1. Monoclinic
2. Triclinic
3. Orthorhombic
• 4. Hexagonal
• 5. Cubic
• 6. Tetragonal
Monoclinic Shape
Gypsum!
Triclinic
Talc
Hexagonal
Calcite
Orthorhombic
Sulfur
Tetragonal
Zircon
Cubic
Crystals
• Crystals can form from magma and solutions of
salts.
• Hot melted rock called magma, cools at or below
Earth’s surface. As magma cools its atoms lose
energy and begin to combine into compounds.
Molecules of the compounds arrange
themselves into repeating patterns.
-When magma cools slowly, the crystals that
form are large.
-When magma cools rapidly, the crystals that
form will be small, so that you cannot easily see
individual crystals.
Crystals
• Crystals can also form from minerals
dissolved in water.
• When water evaporates, the ions that are
left behind can come together to form
crystals. Or, if too much of a substance is
dissolved in water, ions can come together
and form crystals out of solution.
Mineral Groups
• 98% of the Earth’s crust is made of only eight
elements.
• Most of the common rock-forming minerals
belong to the silicates group.
• Silicates are minerals the contain silicon (Si) and
oxygen (o). Silicon and oxygen are the two most
abundant elements in the Earth’s crust.
• Feldspar and quartz are two common silicates.