Transcript Rocks and Minerals

Properties of
Minerals
Vocabulary
Mineral: naturally occurring solid formed by inorganic
process, has crystal structure, definite chemical composition
Crystal: repeating pattern of mineral’s particles forming a
solid
Inorganic: form from materials that were not living
Luster: describes how light reflected from mineral surface
Streak: color of powder
Moh’s hardness scale: used to rank hardness of mineral
Cleavage: mineral splits easily along flat surfaces
Vocabulary
Fracture: describes how mineral looks when it breaks
apart in irregular way
Geode: rounded, hollow rock lined with crystals
Crystallization: process by which atoms arranged to
form material with crystal structure
Solution: mixture one substance dissolved into
another
Vein: narrow channel different from surrounding rock
Defining Minerals
•Naturally occurring
-quartz forms from cooling
magma
-coal- remains plants tightly
squeezed together
•Solid
-definite volume, shape
-particles packed tightly
-coal, quartz
coal
quartz
Mineral Properties
•Crystal structure
-repeating pattern
-flat sides- faces
•Inorganic
-quartz form naturally as magma cools
•Definite chemical comp
-always contains certain elements
-element composed of single atom
Identifying Minerals
metallic
•color- only few have own characteristic color
•Streak: never varies, distinguishing
characteristic
•Luster: metallic, non-metallic
•metallic: shiny, reflective
•Non-metallic: earthy, silky, waxy, pearly
Non-metallic
Hardness
•Rank 1-10
•1: softest
•10: hardest
•Determined by scratch test
•Mineral can scratch mineral softer than
itself
•If it doesn’t scratch- its not hard
Density
•Mass in given space, pass per unit volume
•Always same regardless of size sample
•Mass/ volume
•Heavier sample- more dense
Crystal Structure
•Repeating pattern
•Different minerals- different shapes
•Halite- cubic
•Classify by number faces, sides
•Measure angles at which faces meet
Cleavage, fracture
mica
quartz
•Splits easily flat sheetscleavage
•Depends how crystals
arranged
•Mica
•Fracture- breaks in irregular
way
•Quartz
•Curved, shell like break
How do minerals form
•Crystals form inside geode
•Water containing dissolved
minerals seep into crack, hollow
•Form through organic processes
•Crystallize from materials
dissolved in solutions
•Crystallize as magma, lava cool
Minerals from Solutions
•Elements, compounds dissolve in water leave
solution crystallize
•Minerals form this way in bodies water on Earths
surface
•Selinite crystals form solution hot water underground
Minerals from Magma and Lava
•Minerals form from hot magma
cooling inside crust
•Lava hardens on Earth surface
•Size crystals depends on
-rate crystals cool
-amount of gas magma
contains
-chemical composition
-rich in silicon, oxygen
Minerals Are Crystalline
Geometrical crystal shapes suggest ordered structures.
Minerals from magma
•Magma deep in surface
•Cools slowly
•Larger crystals
•Quartz
•Feldspar
•Tourmaline
•mica
Minerals from lava
•Lava on surface
•Cools quickly
•No time for large crystals to form
•Leucite, olivine