Chapter 3 - Mineralogy

Question 1

requirements of being a mineral

Answer 1

naturally occurring. inorganic. solid. definite chemical composition.

Question 2

what is meant by the term crystalline

Answer 2

reference to any natural solid with an ordered, repetitive, atomic structure

Question 3

crystal

Answer 3

a single, continuous piece of a crystalline solid bounded by crystal surfaces that grew as the mineral formed

Question 4

polymorphs

Answer 4

two different minerals that have the same composition but different crystal structures e.g. carbon polymorphs, diamonds and graphite.

Question 5

solid solution series

Answer 5

the compositional range between minerals that share the same basic chemical formula but experience substitution of element in one or more atomic sites

Question 6

amorphous

Answer 6

a solid in which atoms are not arranged in a definite crystal structure e.g. glass

Question 7

Cleavage

Answer 7

is the tendency to break in preferred directions along reflective planar surfaces. The planar directions along which cleavage occurs are governed by the crystal structure.
Each mineral has characteristic of cleavage or lack of cleavage.
The mica family of minerals all have one direction of cleavage.

Question 8

Fracture

Answer 8

some minerals lack planes of weakness, due to equal molecular bonds in all directions. Thes minerals don’t have cleavage; they fracture e.g. quartz