LESSON 9

Question 1

Modification of the material that does not necessary imply a worsening of its characteristics from the point of view of conservation.

Answer 1

alteration

Question 2

Human perception of the loss of value due to decay.

Answer 2

damage

Question 3

chemical or physical modification of the intrinsic stone properties leading to a loss of value or to the impairment of use.

Answer 3

decay

Question 4

Decline in condition, quality, or functional capacity.

Answer 4

degradation

Question 5

Process of making or becoming worse or lower in quality, value, character, etc.; depreciation.

Answer 5

deterioration

Question 6

Any chemical or mechanical process by which stones exposed to the weather undergo changes in character and deteriorate.

Answer 6

weathering

Question 7

Individual fissure, clearly visible by the naked eye, resulting from separation of one part from another.

Answer 7

crack (fissure)

Question 8

crack sub types:

Answer 8

• fracture
• star crack
• hair crack
• craquele
• splitting

Question 9

Crack that crosses completely the stone piece

Answer 9

fracture

Question 10

Crack having the form of a star. Rusting iron or mechanical impact are possible causes of this type of damage.

Answer 10

star crack

Question 11

Minor crack with width dimension < 0.1 mm

Answer 11

hair crack

Question 12

Network of minor cracks also called crack network. The term crazing is not appropriate for stone, as this term should be used for describing the development of a crack network on glazed terracotta

Answer 12

craquele

Question 13

Fracturing of a stone along planes of weakness such as microcracks or clay/silt layers, in case where the structural elements are orientated vertically.

Answer 13

splitting

Question 14

Change in shape without losing integrity, leading to bending, buckling or twisting of a stone block.

Answer 14

deformation

Question 15

Separated, air-filled, raised hemispherical elevations on the face of stone resulting from the detachment of an outer stone layer. This detachment is not related to the stone structure.

Answer 15

blistering

Question 16

Local loss of the stone surface from internal pressure usually manifesting in the form of an irregularly sided crater.

Answer 16

bursting

Question 17

is sometimes preceded by star-shaped face-fracturing.

Answer 17

bursting

Question 18

loss of material due to a mechanical impact, which may have crater shape if the object hitting the stone surface is hard and small (a bullet for instance).

Answer 18

impact damage

Question 19

Detachment process affecting laminated stones (most of sedimentary rocks, some metamorphic rocks). It corresponds to a physical separation into one or several layers following the stone laminae.

Answer 19

delamination

Question 20

delamination sub type:

Answer 20

exfoliation

Question 21

kind of detachment totally independent of the stone structure.

Answer 21

scaling

Question 21

Detachment of single grains or aggregates of grains.

Answer 21

disintegration

Question 21

detachment of multiple thin stone layers (cm scale) that are sub- parallel to the stone surface. The layers may bend, twist in a similar way as book pages.

Answer 21

exfoliation

Question 22

disintegration sub types:

Answer 22

• crumbling
• granular disintegration

Question 23

Detachment of aggregates of grains from the substrate. These aggregates are generally limited in size (less than 2 cm). This size depends of the nature of the stone and its environment

Answer 23

crumbling

Question 24

Occurs in granular sedimentary (e.g. sandstone) and granular crystalline (e.g. granite) stones.

Answer 24

granular disintegration

Question 25

produces debris referred to as a rock meal and can often be seen accumulating at the foot of wall actively deteriorating.

Answer 25

granular disintegration

Question 26

The following specific terms, all related to granular disintegration, refer either to the size, or to the aspect of corresponding grains:

Answer 26

- powdering or chalking - sugaring - sanding

Question 27

terms sometimes employed for describing granular disintegration of finely grained stones.

Answer 27

powdering or chalking

Question 28

employed mainly for white crystalline marble.

Answer 28

sugaring

Question 29

used to describe granular disintegration of sandstones and granites

Answer 29

sanding