11-14 Stone Deterioration

Question 1

A single or series of surface punctures, holes or gaps, made by a sharp tool or created by an animal. The size is generally of millimetric to centimetric scale. Perforations are deeper than wide, and penetrate into the body of the stone.

Answer 1

Perforation

Question 2

Point-like millimetric or sub millimetric shallow cavities. The pits generally have a cylindrical or conical shape and are not interconnected, although transitions patterns to interconnected pits can also be observed.

Answer 2

Pitting

Question 3

Generally coherent accumulation of materials on the surface.

Answer 3

Crust

Question 4

may include exogenic deposits in combination with materials derived from the stone.

Answer 4

Crust

Question 5

Sub-types of Crust

Answer 5

1. Black Crust
2. Salt Crust

Question 6

Accumulation of exogenic material of variable thickness. Some examples of deposits : splashes of paint or mortar, sea salt aerosols, atmospheric particles such as soot or dust, remains of conservation materials such as cellulose poultices, blast materials etc.

Answer 6

Deposit

Question 7

Change of the stone color in one to three of the color parameters : hue, value and chroma.

Answer 7

Discoloration

Question 8

corresponds to the most prominent characteristic of a color (blue, red, yellow, orange etc.).

Answer 8

hue

Question 9

corresponds to the darkness (low hues) or lightness (high hues) of a color.

Answer 9

value

Question 10

corresponds to the purity of a color.

Answer 10

chroma or saturation

Question 11

Sub-types of discoloration:

Answer 11

• Coloration
• Bleaching
• Moist Area
• Staining

Question 12

Generally whitish, powdery or whisker-like crystals on the surface. Efflorescence’s are generally poorly cohesive and commonly made of soluble salt crystals.

Answer 12

Efflorescence

Question 13

Generally whitish, powdery or whisker-like crystals on the surface. Efflorescence’s are generally poorly cohesive and commonly made of soluble salt crystals.

Answer 13

Encrustation

Question 14

They are generally found below areas of the building where water is percolating or has percolated in the past.

Answer 14

Encrustations

Question 15

Thin covering or coating layer generally of organic nature, generally homogeneous, follows the stone surface. It may be opaque or translucent.

Answer 15

Film

Question 16

Aspect of a surface that reflects totally or partially
the light. The surface has a mirror-like appearance.

Answer 16

Glossy Aspect

Question 17

Engraving, scratching, cutting or application of paint, ink or similar matter on the stone surface.

Answer 17

Graffiti

Question 18

They are generally the result of an act of vandalism.

Answer 18

Graffiti

Question 19

Chromatic modification of the material, generally resulting from natural or artificial ageing and not involving in most cases visible surface deterioration.

Answer 19

Patina

Question 20

Sub-types of Patina:

Answer 20

• Iron rich patina
• oxalate patina

Question 21

Deposit of a very thin layer of exogenous particles (eg. soot) giving a dirty appearance to the stone surface.

Answer 21

Soiling

Question 22

With increasing adhesion and cohesion, soiling can transform into a ______

Answer 22

Crust

Question 23

It may originate from atmospheric pollutants (industrial, domestic or car exhaust products) or from particles transported by running water or heating convection.

Answer 23

Soiling

Question 24

Poorly adhesive soluble salts, commonly white, located under the stone surface.

Answer 24

Sub florescence

Question 25

They are hidden, unless the stone layer over them detaches. In that case, salt crystals become visible on the newly exposed surface.

Answer 25

Calorescences

Question 26

Colonization of the stone by plants and micro-organisms such as bacteria, cyanobacteria, algae, fungi and lichen (symbioses of the latter three).

Answer 26

Biological Colonization

Question 27

It also includes influences by other organisms such as animals nesting on and in stone.

Answer 27

Biological colonization

Question 28

They are microscopic vegetal organisms without stem nor leaves which can be seen outdoors and indoors, as powdery or viscous deposits (thickness : tenth of mm to several mm).

Answer 28

Algae

Question 29

It forms green, red, brown, or black veil like zones and can be found mainly in situations where the substrate remains moistened for long periods of time.

Answer 29

Algae

Question 30

Vegetal organism forming rounded millimetric to centimetric crusty or bushy patches, often having a leathery appearance, growing generally on outside parts of a building.

Answer 30

Lichen

Question 31

They are most commonly grey, yellow, orange, green or black and show no differentiation into stem, root and leaf.

Answer 31

Lichen

Question 32

It is composed of a thallus, eventually bearing fruiting bodies, generally developed on the stone surface, and rhizomes that may penetrate deep into the stone (tens to several millimeters).

Answer 32

Lichen

Question 33

Sub-types of Lichen

Answer 33

Crustose Folious Epilithic Types

Question 34

Vegetal organism forming small, soft and green cushions of centimetric size.

Answer 34

Moss

Question 35

They look generally like dense micro-leaves (sub- to millimetric size) tightly packed together.

Answer 35

Mosses

Question 36

They often grow on stone surface open cavities, cracks, and in any place permanently or frequently wet (masonry joints), and usually shady.

Answer 36

Moss

Question 37

They develop brown rhizines and may create a micro-soil zone between the stone surface and the green part.

Answer 37

Mosses

Question 38

Microscopic fungus which colonies, to the naked eye, look like a downy film or a network or star-like millimetric patches of filaments of diverse colours (white, grey, black).

Answer 38

Mold

Question 39

by their filamentous and/or chain-like growth may penetrate several centimeters into the stone substrate.

Answer 39

Molds

Question 40

Vegetal living being, having, when complete, root, stem, and leaves, though consisting sometimes only of a single leafy expansion (e.g. Tree, fern, herb).

Answer 40

Plant

Question 41

Formation, on the stone surface, of cavities (alveoles) which may be interconnected and may have variable shapes and sizes (generally centimetric, sometimes metric).

Answer 41

Alveolization

Question 42

Loss of original surface, leading to smoothed shapes.

Answer 42

Erosion

Question 43

Sub-types of Erosion

Answer 43

- Differential Erosion - Loss of Components - Loss of matrix - Rounding - Roughening

Question 44

: occurs when erosion does not proceed at the samerate from one area of the stone to the other. As a result, the stone deteriorates irregularly.

Answer 44

Differential Erosion

Question 45

Partial or selective elimination of soft (clay lenticles, nodes of limonite, etc) or compact stone components (pebbles, fossil fragments, geological concretions, lava fragments).

Answer 45

Loss of components

Question 46

Partial or selective elimination of the stone matrix, resulting in protruding compact stone components.

Answer 46

Loss of matrix

Question 47

Preferential erosion of originally angular stone edges leading to a distinctly rounded profile.

Answer 47

Rounding

Question 48

Selective loss of small particles from an originally smooth stone surface.

Answer 48

Roughening

Question 49

Loss of stone material clearly due to a mechanical action.

Answer 49

Mechanical Damage

Question 50

Sub-types of Mechanical Damage:

Answer 50

- Impact Damage - Cut - Scratch - Abrasion - Keying

Question 51

Mechanical damage due to the impact of a projectile (bullet, shrapnel) or of a hard tool.

Answer 51

Impact damage

Question 52

Loss of material due to the action of an edge tool.

Answer 52

Cut

Question 53

Manually induced superficial and line-like loss of material due to the action of some pointed object.

Answer 53

Scratch

Question 54

Erosion due to wearing down or rubbing away by means of friction, or to the impact of particles.

Answer 54

Abrasion

Question 55

Impact damage resulting from hitting a surface with a pointed tool, in order to get an irregular surface which will assist the adhesion of an added material, a mortar for instance.

Answer 55

Keying

Question 56

Network of small interconnected depressions of millimetric to centrimetric scale, sometimes looking like hydrographic network.

Answer 56

Microkarst

Question 57

They are due to a partial and/or selective dissolution of calcareous stone surfaces exposed to water run-off.

Answer 57

Microkarst

Question 58

Empty space, obviously located in the place of some formerly existing stone part.

Answer 58

Missing part

Question 59

Sub-type of Missing Part:

Answer 59

Gap

Question 60

hollow place in the stone surface, hole.

Answer 60

Gap