Definition
Chalk is a soft, white, powdery limestone consisting mainly of fossil shells of foraminifers
Eclogite is an extreme metamorphic rock, formed by regional metamorphism of basalt rock under very high pressure and temperature
History
Origin
-
-
Discoverer
Unknown
René Just Haüy
Etymology
From old English cealc chalk, lime, plaster; pebble, from Greek khalix small pebble, in English transferred to the opaque, white, soft limestone
From French, Greek eklogē selection with reference to the selective content of the rock + -ite1
Class
Sedimentary Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Medium Hardness Rock
Family
Group
-
-
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Clastic or Non-Clastic
Earthy
Color
Grey, White, Yellow
Black, Brown, Green, Grey, Pink, White
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Soft
Dull, Banded and Foilated
Architecture
Interior Uses
Decorative Aggregates, Homes, Interior Decoration
Decorative Aggregates, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration
Paving 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
-
Medical Industry
-
In Chemical and Pharmaceutical Industry, Medicines and Cosmetics
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
Creating Artwork, Gemstone
Types
Chalk Marl and Marl
Eclogite
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, Generally rough to touch, Is one of the oldest rock
Archaeological Significance
Monuments
-
-
Famous Monuments
-
-
Sculpture
-
-
Famous Sculptures
-
-
Pictographs
-
-
Petroglyphs
-
-
Figurines
-
-
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.
Eclogite forms from high-pressure metamorphism of mafic igneous rocks mainly, basalt or gabbro as it plunges into the mantle in a subduction zone.
Composition
Mineral Content
Calcite, Clay, Clay Minerals, Quartz, Sand
Amphibole, Coesite, Corundum, Dolomite, Garnet, Kyanite, Lawsonite, Paragonite, Phengite, Pyroxene, Quartz, Rutile, Zoisite
Compound Content
Ca, NaCl, CaO
Aluminium Oxide, NaCl, CaO, Carbon Dioxide, Iron(III) Oxide, Magnesium Carbonate, MgO, Sodium Oxide, Potassium, Sodium
Transformation
Metamorphism
✔
✘
✔
✘
Types of Metamorphism
-
-
Weathering
✔
✘
✔
✘
Types of Weathering
Biological Weathering, Chemical Weathering
Mechanical Weathering
Erosion
✔
✘
✔
✘
Types of Erosion
Chemical Erosion, Coastal Erosion, Water Erosion
Chemical Erosion, Sea Erosion
Physical Properties
Hardness
13.5-4
1
7
👆🏻
Grain Size
Very fine-grained
Fine Grained
Fracture
-
-
Streak
White
White
Porosity
Highly Porous
Less Porous
Luster
Dull
Subvitreous to Dull
Compressive Strength
5.00 N/mm2200.00 N/mm2
0.15
450
👆🏻
Cleavage
-
Perfect
Toughness
1
-
Specific Gravity
2.3-2.42.86-2.87
0
8.4
👆🏻
Transparency
Opaque
Opaque
Density
2.49-2.50 g/cm33.2-3.6 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
0.90 kJ/Kg K0.75 kJ/Kg K
0.14
3.2
👆🏻
Resistance
Heat Resistant
Heat Resistant
Deposits in Eastern Continents
Asia
Brunei, India, Indonesia, Malaysia, Singapore, Thailand, Vietnam
India, Kazakhstan, Kuwait, Russia, South Korea, Thailand, Turkey
Africa
Cameroon, Chad, Ghana, Kenya, Malawi, Sudan, Tanzania, Togo, Zambia, Zimbabwe
Ethiopia, Morocco, South Africa
Europe
England, France, Germany, Spain, United Kingdom
France, Germany, Italy, Norway, Scotland
Others
-
Greenland
Deposits in Western Continents
North America
Canada, USA
Canada, Costa Rica, Panama, USA
South America
Colombia
Argentina, Brazil, Colombia, Ecuador
Deposits in Oceania Continent
Australia
Adelaide, New Zealand, Queensland, Victoria, Yorke Peninsula
Central Australia, New Zealand, Queensland