Minerals: Color• Color – Many minerals have a characteristic color – Impurities may discolor certain light colored minerals • Ex.. – Dark color minerals typically do not have this... Min
Trang 1Mineral Identification
Mr Jensen
Ref: McGuire – ES/PS
Trang 2Identifying Minerals
• Minerals can be
identified using their
distinctive physical
and chemical
properties
• Mineral properties
include:
– Color – Luster – Hardness – Cleavage – Streak – Characteristics – Composition
Trang 3Table 2-1:
Common
Rock
Forming
Minerals
Trang 4Minerals: Color
• Color
– Many minerals have a
characteristic color
– Impurities may discolor
certain light colored
minerals
• Ex Quartz and calcite
which are typically colorless.
– Dark color minerals
typically do not have this
Trang 5Minerals: Luster
• Luster
– Describes the way light is reflected from the
freshly cut surface of a mineral.
– Metallic Luster
– Non-Metallic Luster
Trang 6Minerals: Streak
• Streak
– The color of the mineral in
a powder form
– The test for streak is
performed by rubbing a
fresh corner of the mineral
across a white, unglazed
streak plate
– Several minerals have a
streak that is not the same
color as the mineral itself
• Most metallic luster minerals
have a dark colored streak
Trang 7Minerals: Crystal Structure
• Crystal Structure
– Minerals form
characteristically
shaped crystals
– A crystal is a regularly
shaped solid formed by
an ordered pattern of
atoms
Trang 8Minerals: Hardness
– Minerals differ in hardness
– Tested by scratching mineral with other materials of known
hardness
– Friedrich Mohs (Geologist) created the Moh’s scale for hardness
Trang 9Minerals: Cleavage
• Cleavage
– If a mineral breaks readily
along flat surfaces it
shows cleavage
– Many minerals break
along flat surfaces called
cleavage planes
– Minerals that break along
even surfaces that do not
follow atomic
arrangement (crystal
faces) are said to show
fracture
Trang 10Minerals: Density
• Density
– Minerals vary in density and specific gravity (ratio of density and water)