Definition
Chalk is a soft, white, powdery limestone consisting mainly of fossil shells of foraminifers
  
Comendite is a hard, peralkaline igneous rock, a type of light blue grey rhyolite
  
History
  
  
Origin
Unknown
  
Italy
  
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
  
Comendite derives its name from the area of Le Commende on San Pietro Island in Italy
  
Class
Sedimentary Rocks
  
Igneous Rocks
  
Sub-Class
Durable Rock, Soft Rock
  
Durable Rock, Hard Rock
  
Family
  
  
Group
Not Applicable
  
Volcanic
  
Other Categories
Fine Grained Rock, Opaque Rock
  
Medium Grained Rock, Opaque Rock
  
Texture
Clastic or Non-Clastic
  
Porphyritic
  
Color
Grey, White, Yellow
  
Blue, Bluish - Grey
  
Maintenance
Less
  
Less
  
Durability
Durable
  
Durable
  
Water Resistant
No
  
Yes
  
Scratch Resistant
No
  
Yes
  
Stain Resistant
No
  
Yes
  
Wind Resistant
No
  
Yes
  
Acid Resistant
No
  
Yes
  
Appearance
Soft
  
Foliated
  
Architecture
  
  
Interior Uses
Decorative Aggregates, Homes, Interior Decoration
  
Countertops, Decorative Aggregates, Interior Decoration
  
Exterior Uses
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration
  
As Building Stone, As Facing Stone, Garden Decoration
  
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, Cement Manufacture, Construction Aggregate, for Road Aggregate, Landscaping, Making natural cement, Raw material for the manufacture of mortar
  
Medical Industry
Not Yet Used
  
Not Yet Used
  
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
  
Artifacts
  
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
  
Cemetery Markers
  
Types
Not Available
  
Rhyolite
  
Features
Clasts are smooth to touch, Is one of the oldest rock, Smooth to touch, Very fine grained rock
  
Very fine grained rock, It is One of the Oldest, Strongest and Hardest Rock
  
Archaeological Significance
  
  
Monuments
Used
  
Not Yet Used
  
Famous Monuments
Data Not Available
  
Not Applicable
  
Sculpture
Used
  
Not Yet Used
  
Famous Sculptures
Data Not Available
  
Not Applicable
  
Pictographs
Used
  
Not Used
  
Petroglyphs
Used
  
Not Used
  
Figurines
Used
  
Not Yet Used
  
Fossils
Present
  
Absent
  
Formation
Chalk is formed from lime mud, which accumulates on the sea floor which is then transformed into rock by geological processes.
  
Comendite is a type of Igneous rock which is formed due to cooling and solidification of lava or magma. It may form with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.
  
Composition
  
  
Mineral Content
Calcite, Clay, Clay Minerals, Quartz, Sand
  
Albite, Amphibole, Quartz
  
Compound Content
Ca, NaCl, CaO
  
Al, Fe, Potassium Oxide
  
Transformation
  
  
Metamorphism
No
  
Yes
  
Types of Metamorphism
Not Applicable
  
Cataclastic Metamorphism, Regional Metamorphism
  
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, Water Erosion
  
Physical Properties
  
  
Hardness
1
  
6-7
  
Grain Size
Very fine-grained
  
Medium Grained
  
Fracture
Not Available
  
Pervasive
  
Streak
White
  
Bluish Black
  
Porosity
Highly Porous
  
Highly Porous
  
Luster
Dull
  
Dull
  
Compressive Strength
Not Available
  
92.40 N/mm
2
  
21
Cleavage
Non-Existent
  
Not Available
  
Toughness
1
  
2
  
Specific Gravity
2.3-2.4
  
2.38
  
Transparency
Opaque
  
Opaque
  
Density
2.49-2.50 g/cm3
  
Not Available
  
Thermal Properties
  
  
Specific Heat Capacity
0.90 kJ/Kg K
  
12
Not Available
  
Resistance
Heat Resistant
  
Heat Resistant, Impact Resistant
  
Deposits in Eastern Continents
  
  
Asia
Brunei, India, Indonesia, Malaysia, Singapore, Thailand, Vietnam
  
China
  
Africa
Cameroon, Chad, Ghana, Kenya, Malawi, Sudan, Tanzania, Togo, Zambia, Zimbabwe
  
East Africa
  
Europe
England, France, Germany, Spain, United Kingdom
  
Italy
  
Others
Not Yet Found
  
Not Yet Found
  
Deposits in Western Continents
  
  
North America
Canada, USA
  
Not Yet Found
  
South America
Colombia
  
Not Yet Found
  
Deposits in Oceania Continent
  
  
Australia
Adelaide, New Zealand, Queensland, Tonga, Victoria, Yorke Peninsula
  
Queensland
  
Chalk vs Comendite 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 Comendite characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Chalk and Properties of Comendite. Learn more about Chalk vs Comendite in the next section. The interior uses of Chalk include Decorative aggregates, Homes and Interior decoration whereas the interior uses of Comendite include Countertops, Decorative aggregates and Interior decoration. Due to some exceptional properties of Chalk and Comendite, 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 Comendite include Building houses or walls, Cement manufacture, Construction aggregate, For road aggregate, Landscaping, Making natural cement, Raw material for the manufacture of mortar.
More about Chalk and Comendite
Here you can know more about Chalk and Comendite. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Chalk and Comendite consists of mineral content and compound content. The mineral content of Chalk includes Calcite, Clay, Clay Minerals, Quartz, Sand and mineral content of Comendite includes Albite, Amphibole, Quartz. You can also check out the list of all . When we have to compare Chalk vs Comendite, the texture, color and appearance plays an important role in determining the type of rock. Chalk is available in grey, white, yellow colors whereas, Comendite is available in blue, bluish - grey colors. Appearance of Chalk is Soft and that of Comendite is Foliated. Properties of rock is another aspect for Chalk vs Comendite. The hardness of Chalk is 1 and that of Comendite is 6-7. The types of Chalk are Not Available whereas types of Comendite are Rhyolite. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Chalk is white while that of Comendite is bluish black. The specific heat capacity of Chalk is 0.90 kJ/Kg K and that of Comendite 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 Comendite is heat resistant, impact resistant.