petrography

Question 1

the identification or interpretation of framework mineralogy and textures leading to classification of wallrock as sedimentary, metamorphic, or igeous

Answer 1

petrography

Question 2

refers to the degree of crystallinity, grain size or granularity, and the fabric

Answer 2

texture

Question 3

consist of wholly of crystals

Answer 3

holocrystalline

Question 4

consist entirely of glass

Answer 4

holohyaline

Question 5

contains both crystals and glass

Answer 5

hypocrystalline

Question 6

extremely minute, incipient crysals, provided they are birefringent

Answer 6

microlites

Question 7

smaller, spherical, rod and hair like isotropic form

Answer 7

crystallite

Question 8

fine grained

Answer 8

aphanitic or eucrystalline

Question 9

coarse grained

Answer 9

phaneritic or dyscrystalline

Question 10

very fine and undistinguishable under petrographic microscope

Answer 10

cryptocrystalline

Question 11

very coarse grained

Answer 11

pegmatitic

Question 12

crystals were bounded completely by crystal faces

Answer 12

euhedral / idiomorphic / automorphic

Question 13

crystals were not bounded by crystal faces

Answer 13

anhedral / allotriomorphic / xenomorphic

Question 14

crystals where partially bounded by crystals

Answer 14

subhedral / hypidiomorphic

Question 15

when one mineral is surrounded by another mineral, the enclosing mineral is the younger

Answer 15

rules of genesis

Question 16

early crystals are generally euhedral or at least more nearly than of later crystals

Answer 16

rules of genesis

Question 17

if both large and small crystals occur together, the laeger one are the first to develop

Answer 17

rules of genesis

Question 18

phenocryst lies in a matrix of glass

Answer 18

vitrophyric texture

Question 19

groundmass is a dense intergrowth of quartz and feldspar

Answer 19

felsophyric texture

Question 20

groundmass of feldspar are rectangular in form instead of slender lath crystals

Answer 20

orthophyric texture

Question 21

phenocryst are clustered into aggregates called glomerocryst or crystal clots

Answer 21

glomeroporphyritic texture

Question 22

glomeroporphyritic texture are formed from a process called?

Answer 22

synneusis

Question 23

crystals, typically phenocrysts, in a igneous rock wchich contains small grains of other minerals

Answer 23

poikilitic texture

Question 24

random plagioclase laths are enclosed by pyroxene or olivine

Answer 24

ophitic texture

Question 25

if the plagioclase is larger and encloses the ferromagnesian minerals (olivine pyr)

Answer 25

subophitic texture

Question 26

angular interstices between feldpar filled with glass instead of pyroxene

Answer 26

hyalophitic texture

Question 27

a border of secondary minerals formed at the margin of a primary grain in an igneous or metamorphic rock -common structure of hydrated ineral in volcanic rocks such as biotite or amphiboles

Answer 27

corona texture / reaction rim / opacitic rim

Question 28

Secondary rim/coronas

Answer 28

kelyphitic rim

Question 29

a crystal occupies the angular spaces between at least two larger crystals

Answer 29

intergranular texture

Question 30

the angular space between larger crystals are occupied by glass or glass and small crystals

Answer 30

intersetal texture

Question 31

texture of a groundmass of a holocrystalline igneous rock in with lath-shaped microlites are arrange in a glass-free mesostasis and are generally interwoven in irregular unoriented fashion

Answer 31

pilotaxitic texture

Question 32

the microlites are parallel, forming flow lines along the direction of lava

Answer 32

trachytic texture

Question 33

an intergrowth of branching rods of quartz set in a single crystal of plagioclase

Answer 33

myrmekitic texture

Question 34

common in plagioclase with combination of zoning patterns and resorption feature butas butas besh

Answer 34

seive texture

Question 35

unmixing of a solid solution

Answer 35

exsolution

Question 36

intimate intergrowth of sodic and potassic feldspar resulting from a subsolidus exsolution

Answer 36

perthitic solution

Question 37

an intergrowth arising due to exsolution where potassic feldspar is present as blebs or lamellae with sodic feldspar

Answer 37

anti-perthitic texture