Schist and Chert
Definition
Definition
Schist is a medium grade metamorphic rock with medium to large, flat, sheet like grains in a preferred orientation
Chert is a hard, dark, opaque sedimentary rock which is composed of silica with an amorphous fine-grained texture
History
Discoverer
Unknown
Unknown
Etymology
From French schiste, Greek skhistos i.e. split
From flint-like quartz, 1670s, of unknown origin- a local term, which has been taken into geological use
Class
Metamorphic Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Family
Group
Not Applicable
Not Applicable
Other Categories
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Texture
Foliated, Platy
Banded, Rough
Color
Black, Blue, Brown, Dark Brown, Green, Grey, Silver
Black, Brown, Green, Grey, Red, White
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
Yes
Yes
Scratch Resistant
No
Yes
Stain Resistant
No
Yes
Wind Resistant
No
No
Acid Resistant
No
Yes
Appearance
Layered and Shiny
Glassy or Pearly
Uses
Architecture
Interior Uses
Decorative Aggregates, Floor Tiles, Interior Decoration
Decorative Aggregates, Homes
Exterior Uses
Garden Decoration, Paving Stone
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings
Other Architectural Uses
Not Yet Used
Curbing
Industry
Construction Industry
As Dimension Stone, Building houses or walls, Cement Manufacture, for Road Aggregate, Roadstone
Arrowheads, Construction Aggregate, Cutting Tool, Spear Points
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts
Artifacts, Monuments
Other Uses
Commercial Uses
Used in aquariums, Writing Slates
Creating Artwork, Gemstone, In fire-starting tools, Jewelry, To ignite fire, Used in flintlock firearms
Types
Types
Mica Schists, Calc-Silicate Schists, Graphite Schists, Blueschists, Whiteschists, Greenschists, Hornblende Schist, Talc Schist, Chlorite Schist, Garnet Schist, Glaucophane schist.
Flint, Jasper, Radiolarite, Common Chert, Chalcedony, Agate, Onyx, Opal, Magadi-type Chert, Porcelanite, Siliceous Sinter
Features
Easily splits into thin plates, Smooth to touch
Clasts are smooth to touch, Easily splits into thin plates, Has High structural resistance against erosion and climate
Archaeological Significance
Monuments
Not Yet Used
Used
Famous Monuments
Not Applicable
Data Not Available
Sculpture
Not Yet Used
Not Yet Used
Famous Sculptures
Not Applicable
Not Applicable
Pictographs
Used
Not Used
Petroglyphs
Used
Not Used
Figurines
Not Yet Used
Not Yet Used
Fossils
Absent
Present
Formation
Formation
Schist formed by dynamic metamorphism at high temperatures and pressures that aligns the grains of mica, hornblende and other elongated minerals into thin layers.
Chert forms when microcrystals of silicon dioxide grow within soft sediments that become limestone or chalk. The chert formation can be either of chemical or biological origin.
Composition
Mineral Content
Alusite, Amphibole, Biotite, Chlorite, Epidote, Feldspar, Garnet, Graphite, Hornblade, Kyanite, Micas, Muscovite or Illite, Porphyroblasts, Quartz, Sillimanite, Staurolite, Talc
Quartz, Silicon
Compound Content
CaO, Carbon Dioxide, MgO
Silicon Dioxide
Transformation
Metamorphism
No
No
Types of Metamorphism
Not Applicable
Not Applicable
Weathering
Yes
No
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Not Applicable
Erosion
Yes
Yes
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Chemical Erosion
Properties
Physical Properties
Hardness
3.5-4
6.5-7
Grain Size
Medium to Fine Coarse Grained
Very fine-grained
Fracture
Conchoidal
Uneven, Splintery or Conchoidal
Streak
White
White
Porosity
Highly Porous
Highly Porous
Luster
Shiny
Waxy and Dull
Compressive Strength
Not Available
450.00 N/mm2
1
Cleavage
Slaty
Non-Existent
Toughness
1.5
1.5
Specific Gravity
2.5-2.9
2.5-2.8
Transparency
Opaque
Translucent to Opaque
Density
2.8-2.9 g/cm3
2.7 g/cm3
Thermal Properties
Specific Heat Capacity
Not Available
0.74 kJ/Kg K
19
Resistance
Impact Resistant, Pressure Resistant, Water Resistant
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Reserves
Deposits in Eastern Continents
Asia
Afghanistan, Bangladesh, Bhutan, China, India, Japan, Kazakhstan, Malaysia, Pakistan, Russia, Thailand, Turkey, Vietnam
China, India, Iran, Japan, Oman, Russia, Saudi Arabia, Taiwan, Thailand, Vietnam
Africa
Egypt, Ethiopia, Morocco, Nigeria, South Africa
Kenya, Morocco, South Africa, Tanzania
Europe
Austria, England, France, Georgia, Germany, Italy, Liechtenstein, Monaco, Norway, Slovenia, Spain, Sweden, Switzerland
Austria, France, Greece, Italy, Malta, Poland, Portugal, Serbia, Spain, Sweden, United Kingdom
Others
Not Yet Found
Greenland, Mid-Atlantic Ridge
Deposits in Western Continents
North America
Canada, Costa Rica, Cuba, Mexico, Panama, USA
Canada, Mexico, USA
South America
Brazil, Colombia, Guyana
Bolivia, Brazil
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Queensland
New South Wales, Queensland, South Australia, Western Australia
All about Schist and Chert Properties
Know all about Schist and Chert properties here. All properties of rocks are important as they define the type of rock and its application. Schist belongs to Metamorphic Rocks while Chert belongs to Sedimentary Rocks.Texture of Schist is Foliated, Platy whereas that of Chert is Banded, Rough. Schist appears Layered and Shiny and Chert appears Glassy or Pearly. The luster of Schist is shiny while that of Chert is waxy and dull. Schist is available in black, blue, brown, dark brown, green, grey, silver colors whereas Chert is available in black, brown, green, grey, red, white colors. The commercial uses of Schist are used in aquariums, writing slates and that of Chert are creating artwork, gemstone, in fire-starting tools, jewelry, to ignite fire, used in flintlock firearms.
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