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Volcanic glass (obsidian) is not a mineral because it is not naturally occurring

ID: 113519 • Letter: V

Question

Volcanic glass (obsidian) is not a mineral because

it is not naturally occurring

it does not have a consistent atomic pattern

it contains no oxygen atoms

a and b

b and c

3 points   

QUESTION 26

Ions of silicon, iron, calcium and other common elements make the rock-forming minerals. What is an ion?

an atom that is not neutral in electric charge

an atoms that has more neutrons than normal

a man-made chemical compound

a kind of atom found only in continental crust (not in oceanic crust)

3 points   

QUESTION 27

Why do silicate minerals make up over 95% of the Earth's crust?

they form a silicon-oxygen tetrahedron

they are based on Si and O ions, both of which are very abundant in the crust

they don't; they make up less than 40% of the crust

none of the above

3 points   

QUESTION 28

The rock-forming minerals quartz and feldspar make up most of the continental crust. Which arrangement of the Si-O tetrahedra do these two minerals have?

isolated

single chain

double chain

sheets

frameworks

a.

it is not naturally occurring

b.

it does not have a consistent atomic pattern

c.

it contains no oxygen atoms

d.

a and b

e.

b and c

Explanation / Answer

Question 25

option d

Obsidian is glass, it is natural and inorganic, but it is amorphous and not crystalline. Therefore it fails one of the 3 key criteria to make it a mineral.

Question 26

option a

an atom that is not neutral in electric charge

Question 27

option a

they form a silicon-oxygen tetrahedron

Question 28

option e frameworks