Earth Materials Lecture 1: Physical properties of Minerals Flashcards
What kind of substance are minerals?
Crystalline substances
Minerals are crystalline substances, this means?
That atoms are arranged in a three dimensional lattice
What do the types of element and their atomic arrangement determine?
The Chemical, physical and optical properties of the mineral.
Is Glass a crystal substance?
No, glass is not a crystal substance, glass is amorphous.
What is an amorphous solid?
An amorphous solid is a solid that lacks a definite atomic structure/pattern. They (the atoms) are arranged more randomly.
List the methods of mineral formation:
-Crystallize from molten rock
-Hydrothermal solutions (water that has been heated to some temperature above ambient surface temperature as a result of natural geologic processes)
-Reaction between lava and water
-In situ during metamorphism
-Cement in sediments
-Precipitation from seawater
What does P-T-X stand for?
Pressure, Temperature, Composition
Where do primary minerals form from?
Directly from magma
Where do secondary minerals form from?
Secondary minerals from through primary minerals being altered, e.g. through metamorphic activity.
List the mineral groups
Native elements
Sulphides
Oxides
Silicates
Halides
Sulphates
Carbonates
Phosphates
Arsenates
Vanadates
List the various physical properties of minerals;
-Habit
-Aggregate form
-Twinning
-Boundary surfaces/Fractures
-Cleavage
Define Habit
The outward morphology of single crystals/external shape of the crystals.
What are the various habit categories to describe minerals?
Prismatic
Pyramidal
Acicular
Fibrous
Blocky
Platy
Botryoidal
Bladed
Define aggregate form
How multiple crystals occur together
Define twinning
crystallographically controlled
intergrowth/ two or more intergrown crystals are formed in a symmetrical fashion.
This may occur through crystal growth, crystal transformation or crystal deformation.
