Chalk and Hornfels
Definition
Definition
Chalk is a soft, white, powdery limestone consisting mainly of fossil shells of foraminifers
Hornfels is a metamorphic rock formed by the contact between mudstone or other clay rich rock, and a hot igneous body, and represents a heat altered equivalent of the original rock
History
Origin
Unknown
New Zealand
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 German which means hornstone
Class
Sedimentary Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Soft Rock
Family
Group
Not Applicable
Not Applicable
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Texture
Clastic or Non-Clastic
Granular, Platy
Color
Grey, White, Yellow
Brown, Dark Greenish - Grey, Green, Reddish Brown
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
No
Yes
Scratch Resistant
No
No
Stain Resistant
No
No
Wind Resistant
No
No
Acid Resistant
No
No
Appearance
Soft
Dull
Uses
Architecture
Interior Uses
Decorative Aggregates, Homes, Interior Decoration
Decorative Aggregates, Flooring, Homes, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
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
for Road Aggregate, Roadstone
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
Artifacts, Monuments
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, Commemorative Tablets, Creating Artwork
Types
Types
Not Available
Biotite hornfels
Features
Clasts are smooth to touch, Is one of the oldest rock, Smooth to touch, Very fine grained rock
Smooth to touch
Archaeological Significance
Monuments
Used
Used
Famous Monuments
Data Not Available
Data Not Available
Sculpture
Used
Not Yet Used
Famous Sculptures
Data Not Available
Not Applicable
Pictographs
Used
Used
Petroglyphs
Used
Used
Figurines
Used
Not Yet Used
Fossils
Present
Absent
Formation
Formation
Chalk is formed from lime mud, which accumulates on the sea floor which is then transformed into rock by geological processes.
Due to change in environmental conditions, rocks are heated and pressurized deep inside the Earth's surface. Hornfels is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.
Composition
Mineral Content
Calcite, Clay, Clay Minerals, Quartz, Sand
Andalusite
Compound Content
Ca, NaCl, CaO
Fe, Mg
Transformation
Metamorphism
No
No
Types of Metamorphism
Not Applicable
Not Applicable
Weathering
Yes
Yes
Types of Weathering
Biological Weathering, Chemical Weathering
Biological Weathering
Erosion
Yes
Yes
Types of Erosion
Chemical Erosion, Coastal Erosion, Water Erosion
Chemical Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Properties
Physical Properties
Hardness
1
2-3
Grain Size
Very fine-grained
Fine Grained
Fracture
Not Available
Conchoidal
Streak
White
Unknown
Porosity
Highly Porous
Highly Porous
Luster
Dull
Shiny
Compressive Strength
Not Available
5.80 N/mm2
31
Cleavage
Non-Existent
Perfect
Toughness
1
Not Yet Found
Specific Gravity
2.3-2.4
3.4-3.9
Transparency
Opaque
Opaque
Density
2.49-2.50 g/cm3
0.25-0.30 g/cm3
Thermal Properties
Specific Heat Capacity
0.90 kJ/Kg K
12
0.84 kJ/Kg K
15
Resistance
Heat Resistant
Heat Resistant, Impact Resistant, Pressure Resistant
Reserves
Deposits in Eastern Continents
Asia
Brunei, India, Indonesia, Malaysia, Singapore, Thailand, Vietnam
Bangladesh, Bhutan, China, India, North Korea, Qatar, Russia, Saudi Arabia, South Korea, Thailand
Africa
Cameroon, Chad, Ghana, Kenya, Malawi, Sudan, Tanzania, Togo, Zambia, Zimbabwe
Cameroon, East Africa, Tanzania, Western Africa
Europe
England, France, Germany, Spain, United Kingdom
United Kingdom
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
Canada, USA
Canada, USA
South America
Colombia
Bolivia, Brazil, Colombia, Ecuador
Deposits in Oceania Continent
Australia
Adelaide, New Zealand, Queensland, Tonga, Victoria, Yorke Peninsula
New South Wales, New Zealand, Queensland, Western Australia
All about Chalk and Hornfels Properties
Know all about Chalk and Hornfels properties here. All properties of rocks are important as they define the type of rock and its application. Chalk belongs to Sedimentary Rocks while Hornfels belongs to Metamorphic Rocks.Texture of Chalk is Clastic or Non-Clastic whereas that of Hornfels is Granular, Platy. Chalk appears Soft and Hornfels appears Dull. The luster of Chalk is dull while that of Hornfels is shiny. Chalk is available in grey, white, yellow colors whereas Hornfels is available in brown, dark greenish - grey, green, reddish brown colors. The commercial uses 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 and that of Hornfels are cemetery markers, commemorative tablets, creating artwork.
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