Minerals

Question 1

Platy

Answer 1

thick sheets stacked together

Question 2

Bladed

Answer 2

elongate crystals that are flattened in one direction

Question 3

Fibrous

Answer 3

composed of hair-like crystals

Question 4

Massive

Answer 4

no clear shapes visible

Question 5

Breakage

Answer 5

the shape of broken surfaces on a mineral crystal which is controlled by the strength of chemical bonds in various directions

Question 6

Cleavage

Answer 6

• form of smooth, planar (flattened) breakage parallel to planes (flat surfaces)
• generally described by the number of clear directions and the angle between them

Question 7

Basal

Answer 7

one well-developed planar (flat surface) cleavage

Question 8

Prismatic

Answer 8

two cleavages

Question 9

Cubic

Answer 9

three cleavages at right angles

Question 10

Rhombohedral

Answer 10

three cleavages not at right angles

Question 11

Octohedral

Answer 11

four cleavages

Question 12

Fracture

Answer 12

non-planar, irregular form of breakage

Question 13

Irregular

Answer 13

rough surface

Question 14

Concoidal

Answer 14

curved surfaces like broken glass

Question 15

Hackly

Answer 15

jagged and sharp

Question 16

Fibrous

Answer 16

long fibers

Question 17

Hardness

Answer 17

mineral’s resistance from scraping

Question 18

Very soft

Answer 18

softer than a finger nail (H<2.5)

Question 19

Soft

Answer 19

harder than a fingernail softer than a penny (2.5>H>3)

Question 20

Intermediate

Answer 20

harder than penny, softer than knife blade (3>H>5.5)

Question 21

Hard

Answer 21

harder than knife blade, softer than porcelain (5.5<H<6.5)

Question 22

Very Hard

Answer 22

Harder than porcelain streak plate (H>6.5)