Mineral Identification

1
Mineral Identification

• Hand Sample

2
Common ID Characteristics

• Color??
• Magnetism
• Luster
• Streak
• Cleavage
• Fracture

• Habit
• Tenacity
• Taste
• Acid Test
• Hardness
• Specific Gravity

3
Color

• Pyrite
• Potassium Feldspar

• Calcite
• Clear
• Orange
• Blue
• White
• Quartz
• Rose quartz
• Amethyst
• Smoky quartz
• Milky quartz
• Clear

4
Magnetism

• The ability of a mineral to align along the
  earths magnetic axis

• Examples
• Magnetite
• Chromite
• Ilmenite

5
Luster

• The reflection of light from the surface of a
  mineral
• Vitreous
• Waxy
• Pearly

6
Streak

• The color of a mineral in its powdered form

• Example
• Hematite - Red

7
Cleavage

• Cleavage planes are controlled by crystal
  structure and symmetry, and reflect the tendency
  of a mineral to break parallel to atomic planes.
  These planes are identified by Miller indices and
  are generally the locations of weaker chemical
  bonds (relative to other bonds within the same
  structure)

8
Cleavage

• 90
• Halite
• 60, 120
• Calcite
• 180
• Mica

9
Fracture

• Bond strength is approximately the same in all
  directions and the breaking of a crystal will not
  follow any particular crystallographic direction

• Conchoidal
• Subconchoidal
• Hackly
• Uneven
• Splintery
• Earthly

10
Habit

• Form in which a mineral grows if there are no
  spatial constraints on its formation

• Prismatic
• Tabular
• Acicular
• Bladed
• Fibrous

• Foliaceous
• Lamellar
• Reticulate
• Scaly

11
Tenacity

• Resistance that a mineral offers to breaking,
  crushing, bending, cutting, or other acts of
  destruction

12
Taste
the sensation that results when taste buds in the
tongue and throat convey information about the
chemical composition of a soluble stimulus
Halite
Sylvite
13
Acid Test
Dissolution reaction of a mineral in response to
the application of an acid

• HCl
• nitric acid
• aqua regia
• 1 part nitric acid, 3-4 parts HCl

Calcite
14
Solubility

• Dissolution of a mineral in pure water

• Nitrates
• Borates
• Carbonates (some)
• Sulfates (some)
• Phosphates (some)

15
Hardness

• Talc
• Gypsum
• Calcite
• Flurospar
• Apatite

• Feldspar
• Quartz
• Topaz
• Corundum
• Diamond

16
Specific Gravity

• The ratio of the weight of a given volume of a
  substance to the weight of an equal volume of
  water

17
For Next Week

• Lab 1
• Due 09/14/2004
• Skim Chapter 2 of Neeses Optical Mineralogy Book