Minerals and Crystals

Question 1

lithified

Answer 1

compacting sediments to form rock

Question 2

mineral

Answer 2

any naturally occurring homogeneous solid that has a definite chemical composition and a distinctive internal crystal strucure

usually formed by inorganic processes

Question 3

rock

Answer 3

any naturally formed earth material which cannot be broken down by hand into its constituent grains, or may be partially broken down by hand into its constituent grains, depending on its weathered condition.

Question 4

soil/superficial deposit

Answer 4

any geologically recent, unlithified, transported material of sedimentary origin

in eng: any naturally formed earth material or fill which can be broken down by hand into its constituent grains.

2 types: weathered soils (in situ) and transported soils (sediments)

Question 5

Mineral Physical Properties

Macroscopic properties

Answer 5

1. Color
2. streak
3. luster
4. cleavage
5. fracture
6. hardness
7. crystal shape
8. specific gravity
9. magnetism
   10.feel
   11.tenacity
   Spotting a free creatures haven, the mammal clung fervently to the staff, cowering lucratively

Question 6

Color

Answer 6

from mineral’s chemical composition, not the most useful in characterizing a mineral especially since some minerals have different colors

Question 7

Luster

Answer 7

the way a mineral’s surface reflects light,

vitreous (glassy), adamantine (brilliant/diamondish)

Question 8

cleavage

Answer 8

bonds between layers of atoms align in certain directions creating weakened directions, breakage occurs parallel to these zones
as many as six cleavage planes may exist
ex:
1, kaolinite, micas
2, feldspars
3, halite (as right angles
3, calcite, dolomite (not at right angles)
4, diamond
6, spalerite

Question 9

Fracture

Answer 9

when bonds between atoms are approximately the same in all directions within a mineral

similar to those formed when thick pieces of glass break

Question 10

Hardness

Answer 10

controlled by the strength of the bonds between atoms and is measured by scratch

Mohs Hardness Scale: comparing hardness to standardized set of minerals (talc to dia)
-this scale is non-linear

Question 11

Crystals

Answer 11

when minerals form in environments where they can grow without interference from neighboring grains

ex: quartz, galena, halite, garnet

Question 12

Specific Gravity

Answer 12

comparison of density to water, can be estimated or found exactly

average:2.6-2.8

Question 13

tenacity

Answer 13

brittle (quartz)
 flexible
 elastic (micas)
 malleable (thin sheets, gold)
 sectile (cut by knife)
 ductile (drawn into wires)

Question 14

Chemical Properties

Answer 14

taste (salt, halite w/ bitter taste) diagnostic

Acid (containing carbonate anion effervesce, calcite)

Question 15

Native Elements (mineral group)

Answer 15

contain one element, (Platinum, Au, Ag, Cu, Sb, S, graphite/diamond C, Hg)

Question 16

gold

Answer 16

Density: 19.3
Hardness: 2.5-3
often with various pyrites sometimes in quartz veins
very malleable

Question 17

Carbonates (mineral group)

Answer 17

metal ion solid soltions
usually medium or low harness
soluble in HCl

Question 18

Calcite

Answer 18

CaCO_3
Density: 2.71
Hardness: 3
most abundant/common mineral
dissolves easily in rain

Question 19

Dolomite

Answer 19

CaMg(CO_3)_2
Hardness: 3.5 to 4
spec grav: 2.85
main source of magnetism

Question 20

Silicates (mineral group)

Answer 20

most commonly occurring minerals

because silica is most abundant constituent of earth’s crust (59 percent)

Question 21

Quartz

Answer 21

Density: 2.6
Hardness: 7
insoluble, important part of granite
some precious stones have same chemical composition but have invisible crystals

Question 22

Orthoclase Feldspars

Answer 22

KAISi_3O_8
Hardness: 6
Luster: vitreous/glassy, streak: white
specific gravity: 2.55-2.63
used in ceramics/glass making

Question 23

Plagioclase Feldspars

Answer 23

usually darker than orthoclase
hardness: 6
streak white, major constituent of earth’s crust

Question 24

Mica

Answer 24

K, Mg, Fe, Al Silicate
density 2.76-3.2
Biotite and Muscovite

Question 25

Hornblende

Answer 25

color: black/dark green
uneven fracture
hardness: 5-6
vitreous to dull
streak brown-grey
specific gravity: 2.9

Question 26

Pyroxene

Answer 26

nonmetallic
cleavage: 2 planes almost 90
hardness: 5.5-6
streak white to pale greenish

Question 27

Olivine

Answer 27

yellow to yellow green 
brittle fracture
hardness: 6.5-7
vitreous
streak: white
spec. gravity: 3.27 - 3.37

Question 28

Clay minerals (mineral group)

Answer 28

end product of weathering
all clay inerals are sheet silicates
Kaolinite, Montmorillonite, bentonite, chlorite, illite
low shear strength

Question 29

Mohrs scale

Answer 29

1 talc
2 gypsum
3 calcite
4 fluorite 
5 apatite
6 feldspar
7 quartz
8 topaz
9 corundum
10 diamond