Minerals Flashcards
What are minerals?
What rocks are made of
What are the five criteria for a mineral?
Solid, inorganic, naturally occurring, fixed chemical formula, atoms in an orderly structure
What defines a non-mineral?
If one or more of the criteria for a mineral is not met
Can the same mineral have different colours?
Yes, there may just be impurities within the mineral
Can different minerals have the same colour?
Yes
How do geologists measure hardness?
Using the Mohs Hardness Scale
What is the range and rule for the Mohs Hardness Scale?
Range: 1-10
Rule: A harder mineral will scratch a softer mineral
What is the lustre of a mineral?
The appearance of reflected light from fresh mineral surfaces
What are the two categories that lustre fits into?
Metallic- Opaque and Non-Metallic- Transparent
What is the streak of a mineral?
The colour of a mineral when it is powdered
Is the streak of a mineral usually the same as its colour in its natural form?
No, it is often different
What is cleavage?
How a mineral breaks along lines of weakness, leaving flat surfaces
How do you judge cleavage?
Look for repeated flat planes on the surface of the sample
What is specific gravity?
A measure of the mass of a mineral compares to the mass of an equal volume of water
Are oils and gases minerals?
No, because they are the decay of living organisms and are not solid
