Hint: Shining gray metallic lustre and deep-red streak are indicative.
Earth Science Quiz 3
Directions: Answer all the questions completely.
Total: 31 points
Section I: Matching
_____Luster A. Light reflected by a mineral
_____Fracture B. Resistance to scratching
_____Streak C. Mass/Volume
_____Hardness D. Breakage along plans of weakness
_____Cleavage E. Breakage not along plans of weakness
_____Specific Gravity F. Color of mineral when powedered
_____Density G. Ratio of the mass of a mineral to mass of an equal volume of water.
Section II: Multiple Choice
_____1. Hardness is a property that helps identify minerals. Scientists use a scale of 1-10 to show the hardness of a mineral. What number would be given to the hardest?
A. 1
B. 4
C. 10
D. 8
_____2. What type of cleavage is parallel to the base of a crystal?
A. Prismatic
B. Basal
C. Cubic
D. Uneven
_____3. What type of luster looks like tar?
A. Pearly
B. Metallic
C. Gumdrop
D. Pitchy
_____4. Which of the following does not describe a mineral’s luster?
A. Pearly
B. Greasy
C. Waxy
D. Conchoidal
_____5. A type of mineral that has a value of 10 on the Mohs hardness scale?
A. Diamond
B. Talc
C. Penny
D. Glass
_____6. What type of luster looks like dirt or dried mud?
A. Dull
B. Earthy
C. Fibrous
D. Adamantine
_____7. What type of fracture resembles broken metal with rough jagged points
A. Uneven
B. Conchoidal
C. Hackly
D. Splintery
_____8. What type of fracture leaves a rough or irregular surface?
A. Uneven
B. Conchoidal
C. Hackly
D. Splintery
Section III: Matching: Match the appropriate mineral grouping to the definition. (8 points)
_____Native Elements
_____Silicates
_____Oxides
_____Sulfates
_____Sulfides
_____Halides
_____Carbonates
_____Phosphates
_____Mineroids
A. This is a category of the pure elements. Most minerals are made up of combinations of chemical elements. In this group a single element like copper is found in a naturally pure form.
B. Is the term used for those substances that do not fit neatly into one of these eight classes
C. Are not as common in occurrence as the other families of minerals. They are often formed when other minerals are broken down by weathering. They are often brightly colored.
D. Are a group of minerals made of carbon, oxygen, and metallic elements. The mineral calcite known as calcium carbonate is the most common in this group.
E. Form from the halogen elements like chlorine, bromine, fluorine, and iodine combined with metallic elements. They are very soft and easily dissolved in water. Halite is a well known example of this group.
F. Are made of compounds of sulfur usually with a metals and oxygen. It is a large group of minerals that tend to be soft, and translucent like barite.
G. Are made of compounds of sulfur usually with a metal. They tend to be heavy and brittle. Several important ores come from this group like pyrite.
H. Form from the combination of a metal with oxygen. This group ranges from dull ores like bauxite to gem like rubies and sapphires.
I. The largest group of minerals. These minerals are made from metals combined with silicon and oxygen.
Section IV: Essay: ( 7 points)
What is the difference between a rock and a mineral and what characteristics do all mineral must possess to be considered a mineral? ( Example: Minerals are naturally occurring)
Section V: 6 points Mineral Identification
Identify these two minerals:
Habit: Excellent cubic cleavage, crystals usually very evident
Lustre: Metallic
Hardness: 2.5
Cleavage: Perfect cubic
Fracture: Subconchoidal
Streak: Lead gray
Rxn w/ Acid: Weak
Magnetism: None
Specific Gravity: 7.6
Hint: Gives off a rotten-egg smell in HCl, very high SG, very metallic lustre.
Habit: Micaceous/tabular habit.
Lustre: Metallic
Hardness: 5 - 6
Cleavage: None
Fracture: Subconchoidal
Streak: Deep red
Rxn w/ Acid: Unknown
Magnetism: None
Specific Gravity: 5.3
Hint: Shining gray metallic lustre and deep-red streak are indicative.