What Makes a Mineral?
What state of matter must a mineral be?
Solid
What property describes the way light reflects from a mineral’s surface?
Luster
What is the tendency of a mineral to split along flat, specific planes called?
Cleavage
A mineral is brassy-colored and has a metallic luster. What property are you observing when you describe how shiny it is?
Luster
What two elements are most abundant in Earth’s crust?
Oxygen and Silicon
Minerals must occur naturally and have this type of internal structure.
A definite crystalline structure
What is the color of a mineral in powdered form called?
Streak
What is it called when a mineral breaks along irregular surfaces?
Fracture
Hematite can appear black, gray, or red, but its streak is usually what color?
Rusty Red
Minerals containing silicon and oxygen are called what?
Silicates
What term describes a mineral made of only one element, such as gold or copper?
Native element
What property describes the amount of light that passes through a mineral?
Transparency
What scale ranks minerals from 1 to 10 based on resistance to scratching?
Mohs hardness scale
A mineral breaks into perfect cubes. What mineral property are you observing?
Cleavage
Which mineral is ranked 10 on the Mohs hardness scale?
Diamond
Why is glass not considered a mineral, even though it can have the same chemical formula as quartz?
Its atoms are not arranged in an orderly, repeating crystalline structure.
Why is color often unreliable for identifying a mineral?
The same mineral can occur in different colors because of impurities or differences in crystal structure.
Which is harder on the Mohs scale: quartz or feldspar?
Quartz
A mineral can be scratched by a penny but not by a fingernail. Its hardness is approximately between what two values?
About 2.5 and 3.5
Both diamond and graphite are made entirely of carbon. Why do they have very different properties?
Their carbon atoms are arranged in different crystal structures.
Name the five criteria used to define a mineral.
Naturally occurring, inorganic, solid, specific chemical composition, and definite crystalline structure
Name four properties geologists can use to identify minerals.
Any four of: color, luster, transparency, shape, streak, hardness, cleavage, fracture, magnetism, or other special properties
Explain the difference between hardness and cleavage.
Hardness describes resistance to scratching; cleavage describes how a mineral breaks along flat planes.
Why should scientists use several properties instead of only one property when identifying an unknown mineral?
Different minerals can share the same color, luster, shape, or other single property, so multiple tests provide stronger evidence for identification.
A mineral is transparent and slightly pink, has a glassy luster, a white streak, breaks into regularly shaped pieces, and can be scratched by a penny but not a fingernail. What mineral is it?
Calcite