Lab 1 Physical Properties

Question 1

Criteria for a mineral

Answer 1

• Regular chemical composition
• Crystalline (atoms in specific, regular, or repeating pattern)
• Must occur in nature

Question 2

Crystal faces

Answer 2

Are the planar sides of a crystal that bound a crystal when the crystal is allowed to grow without restriction

Question 3

Lustre

Answer 3

• Is the appearance of light reflected on the surface of the mineral
• Two types: Metallic and Non-Metallic
• Non-Metallic lustre: glassy, pearly, resinous (smooth plastic), silky (fine fibers), greasy (looks like fat), waxy, dull, and earthy

Question 4

Colour

Answer 4

• Most obvious but least reliable
• Can be used, but not as major identifying feature
• Colour results from the minerals inpurities

Question 5

Streak

Answer 5

• Shows better colour when it is powdered (streak)

- To make streak, swipe the mineral on a streak plate

Question 6

Hardness

Answer 6

The ability of a mineral to resist abrasion or scratching

Question 7

Cleavage

Answer 7

• Cleavage results from the presence of planes of weakness in the atomic network
• Cleavage occurs as step-like segments
• Cleavage planes are parallel

Question 8

Fracture

Answer 8

• Not a planar break

-

Question 9

Planes of Cleavage

Answer 9

0 planes
1 plane
2 planes not at 90
2 planes at 90
3 planes not at 90
3 planes at 90

Question 10

Specific Gravity

Answer 10

• The ratio between the mass of the mineral and the mass of an equal volume of water

Question 11

Habit: Crystal Forms

Answer 11

• The uninterrupted crystal form
• Cube
• Octahedron
• Dodecahedron
• Rhombohedron
• Tetragonal Prism and Pyramid
• Hexagonal Prism
• Hexagonal Prim and Pyramid
• Monoclinic

Question 12

Habit: Crystalline Aggregates

Answer 12

• Granular: an aggregation of grains, lack of distinctive crystal shapes
• Massive: a uniform mass in which individual crystals cant be distinguished
• Fibrous: a grouping of fibres
• Columnar: blocky columns
• Micaceous: a flaky or sheet like groupings
• Oolitic: an aggregation of small spheres
• Botryoidal: resembling a bunch of grapes
• Tabular or Platy: thin plates, but not so thin as sheet

Question 13

Striations

Answer 13

• Fine, thin, parallel grooves on cleavage surfaces or crystal faces
• Affect only the planar surface
• Look for with hand lens