Random Min and Petro

Question 1

second most abundant oxide in the earth’s crust

Answer 1

Al2O3

Question 2

w/c one of the ff minerals has isolated (SiO4)^4 tetrahedra linked by divalent cations in octahedral coordination
a. muscovite
b. quartz
c. beryl
d. olivine

Answer 2

olivine

Question 3

texture characteristic by exosolved lamellae of albite in k-felds is known as

Answer 3

perthite

Question 4

fissility is best shown by

Answer 4

shale

Question 5

among the ff, w/c shows acicular habit:
a. kyanite
b. tourmaline
c. biotite
d. sillimanite

Answer 5

sillimanite

Question 6

also knows as “blue asbestos”

Answer 6

crocidolite

Question 7

IUGS classification:
P - around 80 sa left
Q - around 50 sa right

Answer 7

P - Hazburgite, Q- Wehrlite

Question 8

Match the plutonic rocks in Group 1 with volcanic equivalents in Group 2
Group 1
P. Granite
Q. Syenite
R. Diorite
S. Gabbro

Group 2
1. Andesite
2. Basalt
3. Rhyolite
4. Trachyte

Answer 8

P-3, Q-4, R-1, S-2

Question 9

hardest minerals (w/ exception of diamond) in the Moh’s scale of hardness is
a. an oxide
b. a silicate
c. a phospahte
d. a carbonate

Answer 9

an oxide

Question 10

w/c is not observed under crossed nicols?
a. extinction
b. interference color
c. interference figure
d. pleochroism

Answer 10

pleochroism

Question 11

a becke line test is performed on an unknown mineral surrounded by grains of anorthite (n=1.585) and tremolite (n=1.62). The becke line moves towards the center of the unknown mineral grain along the boundaries where it is in contact with anorthite, but moves outside of the grain boundary where it is in contact with tremolite. what has been determined about the RI of the unknown mineral?

Answer 11

the unknown mineral has a refractive index between 1.585 and 1.62

Question 12

the birefringence of a uniaxial mineral having regractive indices of 1.658 and 1.486 is

Answer 12

0.172
giminus ra ang duha ka given

Question 13

iceland spar is also called transparent

Answer 13

calcite

Question 14

minerals belonging to the ff crystal systems are anistropic, except:
a. monoclinic
b. triniclinic
c. hexagonal
d. isometric

Answer 14

isometric

Question 15

in double refraction, light is split into two rays, namely:

Answer 15

ordinary and extraordinary rays

Question 16

this mineral has a specific gravity >5, hardness <3 and gives grey streak

Answer 16

galena

Question 17

the ff minerals have metallic/submetallic luster, except:
a. graphite
b. sphalerite
c. rutile
d. hematite

Answer 17

rutile

Question 18

w/c of the ff minerals does not show the phenomenon of double refraction
a. quartz
b. fluorite
c. calcite
d. apatite

Answer 18

fluorite

Question 19

w/c of the ff minerals is a good conductor of electricity, besides being strongly magnetic
pyrite
pyrrhotite
cuprite
sphalerite

Answer 19

pyrrhotite

Question 20

a rock described as argillaceous

Answer 20

is clay-rich

Question 21

w/c of the ff represents closed form?
tetragonal prism
dihexagonal pyramid
dome
trigonal dipyramid

Answer 21

trigonal dipyramid