Mineralogy 1

Question 1

arrange the oxides by weight:
Al2O3
CaO
TiO2
H2O
SiO2
MgO
K2O
Na2O
Fe2O3
FeO
Remaining oxides

Answer 1

SiO2
Al2O3
CaO
FeO
Na2O
MgO
K2O
Fe2O3
H2O
TiO2
Remaining oxides

Question 2

olivine, garnet, zircon, kyanite are example of what tetrahedron configuration

Answer 2

Isolated (nesosilicates)

Question 3

epidote, zoisite are example of what tetrahedron configuration

Answer 3

Pairs (sorosilicates)

Question 4

Tourmaline is an example of what tetrahedron configuration

Answer 4

Rings (cyclosilicates)

Question 5

pyroxenes, wollastonite are example of what tetrahedron configuration

Answer 5

single chains (inosilicates)

Question 6

amphiboles are example of what tetrahedron configuration

Answer 6

double chains (inosilicates)

Question 7

Micas, clay minerals, serpentine, chlorite are example of what tetrahedron configuration

Answer 7

sheets (phyllosilicates)

Question 8

felds, quartz, zeolite are example of what tetrahedron configuration

Answer 8

framework (tectosilicates)

Question 9

intergrowth of sodic and potassic felds resulting from subsolidus exosolution (unmixing of two minerals
has blebs or irregular lamellae of sodic feldspar within potassic alkali feldspar

Answer 9

Perthite

Question 10

intergrowth of branching rods of quartz set in a single crystal of plag
derived from the ancient greek work “myrmekia” (wart)

Answer 10

Myrmekite

Question 11

appearance of runic writing
suggested to originate by simultaneous crystallisation

Answer 11

Graphic Texture

Question 12

solid solution phase umixes into two separate phases in the solid state

Answer 12

Exosolution lamellae in pyroxene

Question 13

the same direction in all directions
(garnet, spinel)

Answer 13

equant

Question 14

equant with a nearly square cross sections
(halite, galena)

Answer 14

blocky

Question 15

needlelike
(actinolite, sillimanite)

Answer 15

acicular

Question 16

plates or thick sheet
(gypsum, graphite)

Answer 16

tablular or platy

Question 17

hairlike or threadlike (serpentine, millerite)

Answer 17

capillary or filiform

Question 18

elongated and flatened in one direction (kyanite, wollastonite)

Answer 18

bladed

Question 19

elongated with faces parallel to a common direction (apatite, beryl)

Answer 19

prismatic or columnar

Question 20

easily split into sheets (muscovite, biotite)

Answer 20

foliated or micaceous

Question 21

solid mass with no distinguishing features

Answer 21

massive

Question 22

composed of many individual grains

Answer 22

granular

Question 23

crystals emanating from a common point

Answer 23

radiating or divergent

Question 24

composed of fibers

Answer 24

fibrous

Question 25

stalactite shaped

Answer 25

stalactitic

Question 26

plates or slaps growing together

Answer 26

lamellar or tabular

Question 27

contains aggregate of crystals giving a starlike appearance (pyrophyllite)

Answer 27

stellated

Question 28

feathery appearance

Answer 28

plumose

Question 29

like a branching tree or plant

Answer 29

dendritic or arborescent

Question 30

net-like, lattice pattern

Answer 30

reticulated

Question 31

spherical/hemispherical shapes made of radiating crystals

Answer 31

colloform or globular

Question 32

similar to a bunch of grapes (hematite)

Answer 32

botryoidal

Question 33

kidney-shaped

Answer 33

reniform

Question 34

breast-like

Answer 34

mamillary

Question 35

surfaces covered with fine crystals

Answer 35

drusy

Question 36

small or small spheres

Answer 36

elliptic or pisolitic

Question 37

mineral habit characterized by small, strong and flexible fibers.

Answer 37

asbestiform

Question 38

commercial name for any marketable asbestiform mineral

Answer 38

asbestos

Question 39

"white asbestos" is composed of what mineral? serpentine mineral group accounts for 95% commercial asbestos market

Answer 39

chrysotile

Question 40

"blue asbestos" variety of riebeckite

Answer 40

crocidolite

Question 41

"brown asbestos" variety of grunerite

Answer 41

amosite

Question 42

when a mineral changes color as it is rotated to the polarizer in PPL

Answer 42

pleochroism

Question 43

characterizes the relationship between the speed of light in a vacuum and the speed of light in that mineral

Answer 43

refractive index

Question 44

refractive index of High mineral relief

Answer 44

> 0.12

Question 45

refractive index of intermediate relief

Answer 45

0.04 - 0.12

Question 46

refractive index of low relief

Answer 46

<0.04

Question 47

relative refractive indices of two materials (minerals, glass, or epoxy) adjacent to each other in a thin section can be determined by using

Answer 47

Becke lines

Question 48

if Becke line moves into the mineral grain the mineral has a _____ index of refraction and _____ relief

Answer 48

higher, higher

Question 49

if Becke line move out of the grain, the mineral has a ____ index of refraction and _____ relief

Answer 49

lower, lower

Question 50

ideal crystal form or the shape of a mineral takes when left to grow without barriers or interface with other nearby mineral grains

Answer 50

Mineral form

Question 51

minerals show perfect or nearly perfect crystal faces

Answer 51

euhedral

Question 52

minerals are rounded but still show general characteristic shape of that mineral

Answer 52

subhedral

Question 53

crystals are completely irregular in shape and do not resemble the characteristic form for that mineral

Answer 53

anhedral

Question 54

tendency of minerals to break along atomic planes of weakness within the crystal structure

Answer 54

cleavage

Question 55

irregular cracks within a mineral

Answer 55

fractures

Question 56

under XPL, the mineral will go extinct (dark) when the cleavage direction is PARALLEL to the N-S and E-W directions as the stage is rotated. what extinction is this?

Answer 56

parallel extinction

Question 57

color of mineral under XPL is called

Answer 57

interference color

Question 58

mineral separates into two minerals, producing a striped effect

Answer 58

exosolution lamellae

Question 59

rocks in which clay content is predominant soft in nature and with the presence of water, they crumble easily if dry, crushed easily because of brittleness ex. shale, slate, laterite

Answer 59

argillaceous rocks

Question 60

rocks in w/c calcium carbonate is the major ingredient generally hard but their durability is dependent on surrounding constituents ex. marble, limestone, dolomite

Answer 60

calcareous rocks

Question 61

rocks contain silica in predominant amount presence of a large of free silica makes them harder and durable. strong resistance to weather ex. granite, chert, quartzite

Answer 61

siliceous rocks

Question 62

twinning that has a planar composition surface separating two individual crystals. ex. orthoclase twinned on the Braveno law, with {021} as the twin plane

Answer 62

contact twins

Question 63

twinning that has a planar composition surface separating two individual crystals. ex. crystal of orthoclase twinned on the Braveno law, with {021} as the twin plane

Answer 63

contact twins

Question 64

twinning that have an irregular composition surface separting two individual crystals defined by a twin center or twin axis ex. crystal of orthoclase twinned on the Carlsbad Law with [001] as the twin axis

Answer 64

penetration twins

Question 65

composition surfaces are parallel to one another ex. plagioclase, albite twin law with {010} as the twin plane

Answer 65

polysynthetic twin

Question 66

composition surfaces are not parallel to one another ex. chrysoberyl along {031} plane

Answer 66

cyclical twins

Question 67

feldspar minerals plagioclase and microcline are the most common that show twinning in this system

Answer 67

triclinic system

Question 68

this system is most commonly occur on the plane {100} and {001} orthoclase and sanidine most commonly twinned both contact and penetration twins occur Maneback law {001}, contact twin Carlsbad Law [001], penetration twin Braveno Law {021}, contact twin Swallow Tail Twins {100}, gypsum

Answer 68

monoclinic system

Question 69

commonly twin on planes parallel to a prism face {110} cyclical twins Staurolite Law

Answer 69

orthorhombic crystal (orthorhombic system)

Question 70

twinning in this system usually occurs on {011} forming cyclical contact twins ex. rutile and cassiterite

Answer 70

tetragonal system

Question 71

three types of twins common in isometric system

Answer 71

Spinel Law {111}, spinel [111] Iron cross [001], pyrite