Mineral Identification – Properties

Mineral Identification – Properties
1. Below give the complete definition of a mineral.
A naturally occurring inorganic crystalline solid with a specific chemical formula and structure
2. Are the following items minerals? Explain why or why not. Be complete in your
explanation.
ICE –
Yes. Naturally occurring. No C-H bonds = inorganic yes = crystalline solid with a specific
chemical formula H 2 O and structure = snowflake
OIL –
No. A naturally occurring= OK inorganic = No. It has C-H bonds crystalline = no solid = no
with a specific chemical formula = no and structure
COAL –
No. A naturally occurring= OK inorganic = No. It has C-H bonds crystalline = no solid = yes
with a specific chemical formula = no and structure
3. How is a rock different from a mineral?
A rock contains minerals. A mineral has to be one specific …. Note: a rock can contain one
mineral, but it can also contain things that aren’t minerals.
4. Why is crystal form generally not useful in identifying common mineral samples?
Crystals are often too small to see or not formed when the mineral cooled.
5. What are the two major types of luster we used to identify minerals?
_______________________________ and _______________________________
Metallic and non-metallic.
6. Why is color an unreliable property for identifying minerals (two reasons)?

Different minerals can have the same color(e.g. fluorite and quartz; pyrite and chalcopyrite;
amphibole and pyroxene, etc.) and the same mineral can have different colors. (e.g. rose
quartz, opal quartz, amethyst quartz, smoky quartz, colorless quartz and blue diamond,
chocolate diamond, canary diamond, colorless diamond)
7. What is the hardness of a mineral that cannot be scratched with your fingernail and does
not scratch glass?
Between 5.5 and 2.5
8. What is the hardness of a mineral if it can be scratched by Fluorite but not by Calcite?
Between 3 and 4
9. Define cleavage.
The tendency of a mineral to break along even/ weak planes.
10. Do all minerals exhibit cleavage? _________
No. Some have fracture.
11. Describe the cleavage of mica.
One perfect direction.
12. Quartz does not exhibit cleavage but it does have a unique type of fracture. Name and
describe the type of fracture exhibited by quartz.
Conchoidal Fracture. It scoops out and has sharp edges.
13. Explain two properties of quartz that have been very important in human history.
Conchoidal fracture, chemical resistance, triboluminescence, and resonance
14. Specific gravity is generally used as a property of minerals. Specific gravity is the ratio of
the weight of a mineral to the weight of an equal volume of water. Specific gravity is
closely related to density. Without giving specific mineral names, what type of minerals
tend to have high specific gravity?
Metals

15. Name two minerals that have high specific gravity.
_______________________________ and _____________________________
Galena, magnetite, hematite, sphalerite,
15. What mineral has a salty taste? ______________________
Halite
16. What mineral exhibits double refraction in clear samples? ______________________
Calcite
17. What mineral feels soapy? _________________________
Talc
18. What mineral feels greasy? ________________________
Graphite or halite
19. What mineral is strongly magnetic?_________________________
Magnatite
20. What specific mineral reacts vigorously with hydrochloric acid?_____________________
Calcite
20. If both samples were slightly magnetic, how could someone conclusively distinguish
hematite from magnetite?
The hardness (magnetite scratches glass hematite doesn’t) or the streak.