Definition
Chalk is a soft, white, powdery limestone consisting mainly of fossil shells of foraminifers
  
Skarns are formed during regional or contact metamorphism and from a variety of metasomatic processes involving fluids of magmatic, metamorphic, and/or marine origin
  
History
  
  
Origin
Unknown
  
USA, Australia
  
Discoverer
Unknown
  
Tornebohm
  
Etymology
From old English cealc chalk, lime, plaster; pebble, from Greek khalix small pebble, in English transferred to the opaque, white, soft limestone
  
From an old Swedish mining term originally used to describe a type of silicate gangue or waste rock.
  
Class
Sedimentary Rocks
  
Metamorphic Rocks
  
Sub-Class
Durable Rock, Soft Rock
  
Durable Rock, Hard Rock
  
Family
  
  
Group
Not Applicable
  
Not Applicable
  
Other Categories
Fine Grained Rock, Opaque Rock
  
Fine Grained Rock, Opaque Rock
  
Texture
Clastic or Non-Clastic
  
Earthy, Mud-rich, Rough
  
Color
Grey, White, Yellow
  
Black, Brown, Colourless, Green, Grey, White
  
Maintenance
Less
  
Less
  
Durability
Durable
  
Durable
  
Water Resistant
No
  
Yes
  
Scratch Resistant
No
  
Yes
  
Stain Resistant
No
  
No
  
Wind Resistant
No
  
Yes
  
Acid Resistant
No
  
Yes
  
Appearance
Soft
  
Dull
  
Architecture
  
  
Interior Uses
Decorative Aggregates, Homes, Interior Decoration
  
Decorative Aggregates, Entryways, Interior Decoration
  
Exterior Uses
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration
  
As Building Stone, As Facing Stone, Garden Decoration, 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
  
As a Flux in the Production of Steel and Pig Iron, As a Sintering Agent in Steel Industry to process Iron Ore, As Dimension Stone, Gold and Silver production, Manufacture of Magnesium and Dolomite Refractories
  
Medical Industry
Not Yet Used
  
Not Applicable
  
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
  
Artifacts, Monuments, Sculpture
  
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, Gemstone, Jewelry, Metallurgical Flux, Source of Magnesia (MgO)
  
Types
Not Available
  
Endoskarns
  
Features
Clasts are smooth to touch, Is one of the oldest rock, Smooth to touch, Very fine grained rock
  
Host Rock for Lead, Zinc and Copper Deposits
  
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
  
Not Used
  
Petroglyphs
Used
  
Not Used
  
Figurines
Used
  
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.
  
Due to change in environmental conditions, rocks are heated and pressurized deep inside the Earth's surface. Skarn 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
  
Calcite, Enstatite, Epidote, Garnet, Magnetite, Pyroxene, Titanite
  
Compound Content
Ca, NaCl, CaO
  
Au, CaO, Carbon Dioxide, Cu, Fe, MgO
  
Transformation
  
  
Metamorphism
No
  
Yes
  
Types of Metamorphism
Not Applicable
  
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
  
Weathering
Yes
  
No
  
Types of Weathering
Biological Weathering, Chemical Weathering
  
Not Applicable
  
Erosion
Yes
  
No
  
Types of Erosion
Chemical Erosion, Coastal Erosion, Water Erosion
  
Not Applicable
  
Physical Properties
  
  
Hardness
1
  
6.5
  
Grain Size
Very fine-grained
  
Fine Grained
  
Fracture
Not Available
  
Irregular
  
Streak
White
  
Light to dark brown
  
Porosity
Highly Porous
  
Less Porous
  
Luster
Dull
  
Waxy and Dull
  
Cleavage
Non-Existent
  
Slaty
  
Toughness
1
  
2.4
  
Specific Gravity
2.3-2.4
  
2.86
  
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
0.92 kJ/Kg K
  
10
Resistance
Heat Resistant
  
Heat Resistant
  
Deposits in Eastern Continents
  
  
Asia
Brunei, India, Indonesia, Malaysia, Singapore, Thailand, Vietnam
  
China, India, Russia, Saudi Arabia, South Korea, Sri Lanka
  
Africa
Cameroon, Chad, Ghana, Kenya, Malawi, Sudan, Tanzania, Togo, Zambia, Zimbabwe
  
South Africa, 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
  
South America
Colombia
  
Brazil, Colombia, Paraguay
  
Deposits in Oceania Continent
  
  
Australia
Adelaide, New Zealand, Queensland, Tonga, Victoria, Yorke Peninsula
  
Central Australia, Western Australia
  
All about Chalk and Skarn Properties
Know all about Chalk and Skarn properties here. All properties of rocks are important as they define the type of rock and its application. Chalk belongs to Sedimentary Rocks while Skarn belongs to Metamorphic Rocks.Texture of Chalk is Clastic or Non-Clastic whereas that of Skarn is Earthy, Mud-rich, Rough. Chalk appears Soft and Skarn appears Dull. The luster of Chalk is dull while that of Skarn is waxy and dull. Chalk is available in grey, white, yellow colors whereas Skarn is available in black, brown, colourless, green, grey, white 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 Skarn are creating artwork, gemstone, jewelry, metallurgical flux, source of magnesia (mgo).