Lecture 4: Minerals Flashcards
Minerals are:
Naturally occurring Inorganic Homogeneous solid Definite chemical composition Ordered internal structure
“All _______ are ________ but not all _________ are __________”
crystals, minerals
All minerals are crystals but not all crystals are minerals
different minerals, same composition, different structure
Polymorphism
different minerals, different composition, same structure
Isomorphism
Give example of polymorphism
Pyrite and Marcasite (FeS2)
Give example of isomorphism
Halite and Pyrite
Building block of mineral that repeats itself
unit cell
Mineral-like substances which are either amorphous (no crystalline structure) or organic in nature
Mineraloid
Mineraloid difference in minerals
Either amorphous (no crystalline structure) or organic
A property of mineral that is caused by the absorption or reflection of light; it is not a reliable diagnostic property
color
Mineral color is observed as shades of one color
Idiochromatic
mineral colors may be varied
Allochromatic
color of a mineral in powdered form (streak plate)
Streak
*metallic mineral: _____ streak
dark colored streaks
non-metallic mineral: ________ streak
white streak
A property of mineral that is defined as the ability of minerals to reflect light
Luster
coherent reflection of light =
brighter = more luster
Refers to the state of being opaque, translucent, and/or transparent
Diaphaneity
shapes and aggregates that a certain mineral is likely to form
Habit
resistance to scratching or abrasion
Hardness
Moh’s scale of Hardness:
10 - Diamond 9 - Corundum 8 - Topaz 7 – Quartz 6.5 – streak plate 6 – Orthoclase 5.5 – Glass and knife blade 5 – Apatite 4.5 – wire nail 4 – Fluorite 3.5 – Copper penny 3 – Calcite 2.5 - Fingernail 2 - Gypsum 1 – Talc
How do the hardness of the index materials increase in the Moh’s scale
It increases exponentially
smooth, repetitive, planar (or parallel) planes where chemical bonds are weak or where a mineral would tend to break or cleave.
Cleavage
To satisfy the definition of cleavage, it must be
Smooth, repetitive, planar (or parallel)
when chemical bond are uniform in strength in all directions
Fracture
“when you don’t have cleavage, you have _____”
fracture
Other properties of Minerals:
Specific Gravity
Effervescence
Magnetism
Specific gravity =
volume of substance/ weight of the same volume of water
Define effervescence
Reaction of acid (fizz sound); of carbonate (CaCO3) calcite
Give examples of luster
metallic (very coherent reflection of light), submetallic (medyo), vitreous (glass-like), greasy (oily), silky, pearly, earthy (hindi nagrereflect ng light), resinous (amber: Sphalerite)
MS V GaSPER
What is the habit of olivine?
Saccharoidal (sugar-like)
Olivine: main component of peridotites or mantle rock
Give examples of habit
bladed, prismatic, fibrous, banded, botryoidal, acicular, saccharoidal, cubic, platty, rosette
FB SA PBB CPR
Color and streak of pyrite
Brass yellow color, greenish black streak
Example of mineraloid
Pearls and Obsidian
What is the luster of Sphalerite (ZnS)
Resinous (amber)
Why do crystals differ in habit
Because habit is based on the ratio of your x,y,z axes
Important source of Titanium
Ilmenite
Color of
Azurite, Sulfur, Emerald
Blue, Yellow, Green
Color of
Tangerine Quartz, Amethyst, Garnet
Orange, Purple, Red
