Identification of Minerals

Question 1

function of the wavelength of the mineral

Answer 1

color

Question 2

ability to absorb different wavelengths based on crystallographic orientation

Answer 2

pleochroism

Question 3

what crystal systems display dichroic pleochroism

Answer 3

hexagonal and tetragonal

Question 4

what crystal systems display trichroic pleochroism

Answer 4

orthorhombic, monoclinic, and triclinic

Question 5

darkest pleochroism at long axis perpendicular

Answer 5

normal pleochroism

Question 6

darkest at long axis parallel

Answer 6

reverse pleochroism

Question 7

the degree to which a mineral stands out

Answer 7

relief

Question 8

without regular crystal faces

Answer 8

anhedral

Question 9

well formed crystal faces

Answer 9

euhedral

Question 10

poorly formed crystal faces

Answer 10

subhedral

Question 11

elongate needlelike grains

Answer 11

acicular

Question 12

elongate, slender grains

Answer 12

bladed

Question 13

shaped like a column

Answer 13

columnar

Question 14

equidimensional grains

Answer 14

equant

Question 15

long and slender grains

Answer 15

fibrous

Question 16

flat elongate grains

Answer 16

lathlike

Question 17

prism like grains

Answer 17

prismatic

Question 18

shaped like a book

Answer 18

tabular

Question 19

parallel columnar grains

Answer 19

columnar

Question 20

parallel tabular grains

Answer 20

foliated

Question 21

equant grains

Answer 21

granular

Question 22

random elongate grains

Answer 22

matted

Question 23

radiating elongate grains

Answer 23

radiating

Question 24

the way a mineral splits in preferred directions

Answer 24

cleavage

Question 25

the wavelength of a mineral under XPL

Answer 25

interference color

Question 26

at what angle can maximum interference be viewed

Answer 26

45° from extinction

Question 27

extinct when cleavage is NS or EW

Answer 27

parallel

Question 28

extinct when cleavage is not NS and EW

Answer 28

Inclined

Question 29

extinct when the intersection of the cleavages are NS and EW

Answer 29

symmetrical

Question 30

different parts become extinct at different angles

Answer 30

undulose

Question 31

to determine what ray is going through the mineral

Answer 31

sign of elongation

Question 32

higher interference color is produced upon elongation

Answer 32

length-slow

Question 33

lower interference color is produced at elongation

Answer 33

length-fast

Question 34

one lambda is equal to

Answer 34

500nm

Question 35

lambda of muscovite/mica plate

Answer 35

1/4

Question 36

lambda of gypsum plate

Answer 36

1

Question 37

intergrowth of two or more minerals

Answer 37

twinning

Question 38

zoned extinction

Answer 38

zoning