Mineral Basics
What is a naturally occurring, inorganic solid with a definite chemical composition and crystal structure?
A mineral
What property describes how light reflects from a mineral?
Luster
What is the softest mineral on the Mohs Hardness Scale?
talc
What are the three main rock types?
Igneous, sedimentary, and metamorphic.
What process changes magma or lava into igneous rock?
Cooling and solidification
This famous British band shares its name with a geology idea: a rock that keeps moving is less likely to gather moss.
The Rolling Stones
What is a rock?
A solid mixture made of one or more minerals or mineral-like materials.
What property is the color of a mineral’s powder?
Streak
What is the hardest mineral on the Mohs Hardness Scale?
Diamond
Which rock type forms when magma or lava cools and solidifies?
Igneous rock
What process changes rock into sediment?
Weathering and erosion
What is one difference between a rock and a mineral?
A mineral has a definite composition and crystal structure, while a rock can be made of several minerals.
What property measures resistance to scratching?
Hardness
Quartz has a hardness of 7 and feldspar has a hardness of 6. Which one can scratch the other?
Quartz can scratch feldspar.
Which rock type forms from compacted and cemented sediment?
Sedimentary rock
What process changes existing rock into metamorphic rock?
Heat and pressure
Why is glass not considered a mineral?
It does not have an orderly crystal structure.
What is the difference between cleavage and fracture?
Cleavage breaks along smooth, flat planes; fracture breaks irregularly.
What does density compare?
Mass and volume
Which rock type forms when existing rock changes because of heat and pressure?
Metamorphic rock
Can one rock type eventually become another rock type?
Yes. Rocks can change through different rock-cycle processes.
Name the five requirements for something to be considered a mineral.
Naturally occurring, inorganic, solid, definite chemical composition, and crystal structure.
Why can streak be more useful than surface color when identifying a mineral?
Surface color can change due to weathering, while streak is often more consistent.
Two minerals are the same size, but one feels heavier. Which one likely has the greater density?
the heavier one
Why is melting not part of metamorphism?
Metamorphic rock changes because of heat and pressure without completely melting. If it melts, it becomes magma instead.
A metamorphic rock is exposed at Earth’s surface. Describe one possible pathway that could eventually turn it into igneous rock.
metamorphic rock → melting → magma/lava → cooling and solidification → igneous rock.