Comendite and Chalk
Definition
Definition
Comendite is a hard, peralkaline igneous rock, a type of light blue grey rhyolite
Chalk is a soft, white, powdery limestone consisting mainly of fossil shells of foraminifers
History
Origin
Italy
Unknown
Discoverer
Unknown
Unknown
Etymology
Comendite derives its name from the area of Le Commende on San Pietro Island in Italy
From old English cealc chalk, lime, plaster; pebble, from Greek khalix small pebble, in English transferred to the opaque, white, soft limestone
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Soft Rock
Family
Group
Volcanic
Not Applicable
Other Categories
Medium Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Texture
Porphyritic
Clastic or Non-Clastic
Color
Blue, Bluish - Grey
Grey, White, Yellow
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
Yes
No
Scratch Resistant
Yes
No
Stain Resistant
Yes
No
Wind Resistant
Yes
No
Acid Resistant
Yes
No
Appearance
Foliated
Soft
Uses
Architecture
Interior Uses
Countertops, Decorative Aggregates, Interior Decoration
Decorative Aggregates, Homes, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration
Other Architectural Uses
Curbing
Powder
Industry
Construction Industry
Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate, Landscaping, Making natural cement, Raw material for the manufacture of mortar
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
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts
Artifacts, Monuments, Sculpture, Small Figurines
Other Uses
Commercial Uses
Cemetery Markers
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
Types
Types
Rhyolite
Not Available
Features
Very fine grained rock, It is One of the Oldest, Strongest and Hardest Rock
Clasts are smooth to touch, Is one of the oldest rock, Smooth to touch, Very fine grained rock
Archaeological Significance
Monuments
Not Yet Used
Used
Famous Monuments
Not Applicable
Data Not Available
Sculpture
Not Yet Used
Used
Famous Sculptures
Not Applicable
Data Not Available
Pictographs
Not Used
Used
Petroglyphs
Not Used
Used
Figurines
Not Yet Used
Used
Fossils
Absent
Present
Formation
Formation
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.
Chalk is formed from lime mud, which accumulates on the sea floor which is then transformed into rock by geological processes.
Composition
Mineral Content
Albite, Amphibole, Quartz
Calcite, Clay, Clay Minerals, Quartz, Sand
Compound Content
Al, Fe, Potassium Oxide
Ca, NaCl, CaO
Transformation
Metamorphism
Yes
No
Types of Metamorphism
Cataclastic Metamorphism, Regional Metamorphism
Not Applicable
Weathering
Yes
Yes
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering
Erosion
Yes
Yes
Types of Erosion
Coastal Erosion, Water Erosion
Chemical Erosion, Coastal Erosion, Water Erosion
Properties
Physical Properties
Hardness
6-7
1
Grain Size
Medium Grained
Very fine-grained
Fracture
Pervasive
Not Available
Streak
Bluish Black
White
Porosity
Highly Porous
Highly Porous
Luster
Dull
Dull
Compressive Strength
92.40 N/mm2
21
Not Available
Cleavage
Not Available
Non-Existent
Toughness
2
1
Specific Gravity
2.38
2.3-2.4
Transparency
Opaque
Opaque
Density
Not Available
2.49-2.50 g/cm3
Thermal Properties
Specific Heat Capacity
Not Available
0.90 kJ/Kg K
12
Resistance
Heat Resistant, Impact Resistant
Heat Resistant
Reserves
Deposits in Eastern Continents
Asia
China
Brunei, India, Indonesia, Malaysia, Singapore, Thailand, Vietnam
Africa
East Africa
Cameroon, Chad, Ghana, Kenya, Malawi, Sudan, Tanzania, Togo, Zambia, Zimbabwe
Europe
Italy
England, France, Germany, Spain, United Kingdom
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
Not Yet Found
Canada, USA
South America
Not Yet Found
Colombia
Deposits in Oceania Continent
Australia
Queensland
Adelaide, New Zealand, Queensland, Tonga, Victoria, Yorke Peninsula
All about Comendite and Chalk Properties
Know all about Comendite and Chalk properties here. All properties of rocks are important as they define the type of rock and its application. Comendite belongs to Igneous Rocks while Chalk belongs to Sedimentary Rocks.Texture of Comendite is Porphyritic whereas that of Chalk is Clastic or Non-Clastic. Comendite appears Foliated and Chalk appears Soft. The luster of Comendite and Chalk is dull. Comendite is available in blue, bluish - grey colors whereas Chalk is available in grey, white, yellow colors. The commercial uses of Comendite are cemetery markers and that of Chalk are 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.
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