Definition
Chalk is a soft, white, powdery limestone consisting mainly of fossil shells of foraminifers
  
Coquina is a sedimentary rock that is composed either wholly or almost entirely of the transported, abraded, and mechanically-sorted fragments of the shells of molluscs, trilobites, brachiopods, or other invertebrates
  
History
  
  
Origin
Unknown
  
European Foreland Basins
  
Discoverer
Unknown
  
Unknown
  
Etymology
From old English cealc chalk, lime, plaster; pebble, from Greek khalix small pebble, in English transferred to the opaque, white, soft limestone
  
From Concha (Latin)+ Coquina(Spanish) +conch(English)= Couquina (mid 19th century)
  
Class
Sedimentary Rocks
  
Sedimentary Rocks
  
Sub-Class
Durable Rock, Soft Rock
  
Durable Rock, Soft Rock
  
Family
  
  
Group
Not Applicable
  
Not Applicable
  
Other Categories
Fine Grained Rock, Opaque Rock
  
Coarse Grained Rock, Opaque Rock
  
Texture
Clastic or Non-Clastic
  
Clastic
  
Color
Grey, White, Yellow
  
Beige, Buff, Orange
  
Maintenance
Less
  
More
  
Durability
Durable
  
Non-Durable
  
Water Resistant
No
  
No
  
Scratch Resistant
No
  
No
  
Stain Resistant
No
  
No
  
Wind Resistant
No
  
No
  
Acid Resistant
No
  
No
  
Appearance
Soft
  
Layered, Banded, Veined and Shiny
  
Architecture
  
  
Interior Uses
Decorative Aggregates, Homes, Interior Decoration
  
Decorative Aggregates, Homes, Hotels, Interior Decoration
  
Exterior Uses
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration
  
Garden Decoration, Office Buildings
  
Other Architectural Uses
Powder
  
Curbing
  
Industry
  
  
Construction Industry
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate, Making natural cement, raw material for manufacture of quicklime and slaked lime, Source of calcium
  
Building houses or walls, Construction Aggregate
  
Medical Industry
Not Yet Used
  
Not Yet Used
  
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
  
Artifacts, Monuments, Sculpture, Small Figurines
  
Other Uses
  
  
Commercial Uses
Alumina Refineries, Creating Artwork, Drawing on blackboards, Gymnasts, athletes and mountain climbers use for grip, In aquifers, Paper Industry, Production of Lime, Raw material for manufacture of quicklime, slaked lime, Soil Conditioner, Whiting, Whiting material in toothpaste, paint and paper
  
Creating Artwork
  
Types
Not Available
  
Not Available
  
Features
Clasts are smooth to touch, Is one of the oldest rock, Smooth to touch, Very fine grained rock
  
Available in Lots of Colors and Patterns, Is one of the oldest rock
  
Archaeological Significance
  
  
Monuments
Used
  
Used
  
Famous Monuments
Data Not Available
  
Data Not Available
  
Sculpture
Used
  
Used
  
Famous Sculptures
Data Not Available
  
Data Not Available
  
Pictographs
Used
  
Used
  
Petroglyphs
Used
  
Used
  
Figurines
Used
  
Used
  
Fossils
Present
  
Present
  
Formation
Chalk is formed from lime mud, which accumulates on the sea floor which is then transformed into rock by geological processes.
  
Coquina is a sedimentary rock which is formed when billions of small clam-like seashell, called Coquina, or cockleshell are die and hence are deposited, buried and turns into a rock when pressure is applied.
  
Composition
  
  
Mineral Content
Calcite, Clay, Clay Minerals, Quartz, Sand
  
Apatite, Augite, Bronzite, Calcite, Chert, Chlorite, Clay Minerals, Epidote, Feldspar, Garnet, Micas, Muscovite or Illite
  
Compound Content
Ca, NaCl, CaO
  
CaO, Carbon Dioxide, Iron(III) Oxide, MgO
  
Transformation
  
  
Metamorphism
No
  
No
  
Types of Metamorphism
Not Applicable
  
Not Applicable
  
Weathering
Yes
  
Yes
  
Types of Weathering
Biological Weathering, Chemical Weathering
  
Biological Weathering, Chemical Weathering, Mechanical Weathering
  
Erosion
Yes
  
Yes
  
Types of Erosion
Chemical Erosion, Coastal Erosion, Water Erosion
  
Coastal Erosion, Sea Erosion, Water Erosion, Wind Erosion
  
Physical Properties
  
  
Hardness
1
  
1-2
  
Grain Size
Very fine-grained
  
Coarse Grained
  
Fracture
Not Available
  
Irregular
  
Streak
White
  
White
  
Porosity
Highly Porous
  
Highly Porous
  
Luster
Dull
  
Dull to Vitreous to Submetallic
  
Cleavage
Non-Existent
  
Not Available
  
Toughness
1
  
Not Available
  
Specific Gravity
2.3-2.4
  
1.10-2.24
  
Transparency
Opaque
  
Opaque
  
Density
2.49-2.50 g/cm3
  
2.8-2.9 g/cm3
  
Thermal Properties
  
  
Specific Heat Capacity
0.90 kJ/Kg K
  
12
Not Available
  
Resistance
Heat Resistant
  
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
  
Deposits in Eastern Continents
  
  
Asia
Brunei, India, Indonesia, Malaysia, Singapore, Thailand, Vietnam
  
Not Yet Found
  
Africa
Cameroon, Chad, Ghana, Kenya, Malawi, Sudan, Tanzania, Togo, Zambia, Zimbabwe
  
Not Yet Found
  
Europe
England, France, Germany, Spain, United Kingdom
  
United Kingdom
  
Others
Not Yet Found
  
Not Yet Found
  
Deposits in Western Continents
  
  
North America
Canada, USA
  
USA
  
South America
Colombia
  
Not Yet Found
  
Deposits in Oceania Continent
  
  
Australia
Adelaide, New Zealand, Queensland, Tonga, Victoria, Yorke Peninsula
  
Not Yet Found
  
Chalk vs Coquina Characteristics
Though some rocks look identical, they have certain characteristics which distinguish them from others. Characteristics of rocks include texture, appearance, color, fracture, streak, hardness etc. Chalk vs Coquina characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Chalk and Properties of Coquina. Learn more about Chalk vs Coquina in the next section. The interior uses of Chalk include Decorative aggregates, Homes and Interior decoration whereas the interior uses of Coquina include Decorative aggregates, Homes, Hotels and Interior decoration. Due to some exceptional properties of Chalk and Coquina, they have various applications in construction industry. The uses of Chalk in construction industry include As dimension stone, Cement manufacture, Construction aggregate, For road aggregate, Making natural cement, Raw material for manufacture of quicklime and slaked lime, Source of calcium and that of Coquina include Building houses or walls, Construction aggregate.
More about Chalk and Coquina
Here you can know more about Chalk and Coquina. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Chalk and Coquina consists of mineral content and compound content. The mineral content of Chalk includes Calcite, Clay, Clay Minerals, Quartz, Sand and mineral content of Coquina includes Apatite, Augite, Bronzite, Calcite, Chert, Chlorite, Clay Minerals, Epidote, Feldspar, Garnet, Micas, Muscovite or Illite. You can also check out the list of all Sedimentary Rocks. When we have to compare Chalk vs Coquina, the texture, color and appearance plays an important role in determining the type of rock. Chalk is available in grey, white, yellow colors whereas, Coquina is available in beige, buff, orange colors. Appearance of Chalk is Soft and that of Coquina is Layered, Banded, Veined and Shiny. Properties of rock is another aspect for Chalk vs Coquina. The hardness of Chalk is 1 and that of Coquina is 1-2. The types of Chalk are Not Available whereas types of Coquina are Not Available. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Chalk and Coquina is white. The specific heat capacity of Chalk is 0.90 kJ/Kg K and that of Coquina is Not Available. Depending on the properties like hardness, toughness, specific heat capacity, porosity etc., rocks are resistant to heat, wear, impact, etc.Chalk is heat resistant whereas Coquina is heat resistant, impact resistant, pressure resistant, wear resistant.