Describing Minerals

Question 1

ideal conditions –>

Answer 1

perfect crystallization

Question 2

Habit

Answer 2

crystal shape

Question 3

terminations

Answer 3

crystal faces that close off crystal

Question 4

prismatic faces

Answer 4

pinacoids, equal and opposite pairs of faces

Question 5

subhedral

Answer 5

almost euhedral, not perfect

Question 6

auhedral

Answer 6

cruved and linear edges, not original shape

Question 7

crystals can grow in

Answer 7

cavaties, ex quatz in lava, geodes

Question 8

special habit such as branching and dendrites

Answer 8

can indicate rapid grwoth, perserved in enevironment that doesnt rip or bend etc

Question 9

Massive crystal

Answer 9

when its impossible to tell wether specimen is single anhedral or mass of anhedral crystals

Question 10

Colour in Minerals

Answer 10

some colour producing elements
structural components or colour centers created colours
some transition metals responsible for colours

Question 11

inclusions in minerals

Answer 11

inclusions can be other minerals or gas or liquid phases

Question 12

smallest unit of crystal

Answer 12

smallest unit of a crystal is the unit cell, but always bigger than unit cell

Question 13

smallest crystals formed from

Answer 13

iron oxides and clay minerals form smallest crystals

Question 14

cryptocrystalline

Answer 14

cryptocrystalline: finely crystalline minerals

Question 15

obsidian

Answer 15

formed glass, amorphous

Question 16

amorphous minerals

Answer 16

Amorphous materials are non-crystalline, that is they lack long-range regularity in their atomic structure. By definition they cannot be minerals. Nevertheless, some natural amorphous substances have been accepted as minerals.
some mineral have amorphous phases

Question 17

opal

Answer 17

opal formed from spheres of hydro colloidal silica