Definition
Schist is a medium grade metamorphic rock with medium to large, flat, sheet like grains in a preferred orientation
Adakite is an intermediate to felsic volcanic rock that has geochemical characteristics of magma which is said to be formed by partial melting of altered basalt that is subducted below volcanic arcs
Origin
Unknown
Adak, Aleutian Islands
Discoverer
Unknown
Defant and Drummond
Etymology
From French schiste, Greek skhistos i.e. split
From Adak, Aleutian Islands
Class
Metamorphic Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Medium Hardness Rock
Group
Not Applicable
Volcanic
Other Categories
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Foliated, Platy
Porphyritic
Color
Black, Blue, Brown, Dark Brown, Green, Grey, Silver
Black, Brown, Light to Dark Grey
Durability
Durable
Durable
Appearance
Layered and Shiny
Dull and Soft
Interior Uses
Decorative Aggregates, Floor Tiles, Interior Decoration
Decorative Aggregates, Floor Tiles, Homes, Hotels, Kitchens
Exterior Uses
Garden Decoration, Paving Stone
As Building Stone, As Facing Stone, Office Buildings
Other Architectural Uses
Not Yet Used
Whetstones
Construction Industry
As Dimension Stone, Building houses or walls, Cement Manufacture, for Road Aggregate, Roadstone
As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts
Monuments, Sculpture, Small Figurines
Commercial Uses
Used in aquariums, Writing Slates
Commemorative Tablets, Pottery, Used in aquariums
Types
Mica Schists, Calc-Silicate Schists, Graphite Schists, Blueschists, Whiteschists, Greenschists, Hornblende Schist, Talc Schist, Chlorite Schist, Garnet Schist, Glaucophane schist.
Not Available
Features
Easily splits into thin plates, Smooth to touch
Has High structural resistance against erosion and climate, Host rock for Diamond, 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
Figurines
Not Yet Used
Used
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.
Adakite rocks are formed when the hydrous fluids are released from minerals that break down in metamorphosed basalt, and rise into the mantle they initiate partial melting.
Mineral Content
Alusite, Amphibole, Biotite, Chlorite, Epidote, Feldspar, Garnet, Graphite, Hornblade, Kyanite, Micas, Muscovite or Illite, Porphyroblasts, Quartz, Sillimanite, Staurolite, Talc
Olivine, Plagioclase, Pyroxene
Compound Content
CaO, Carbon Dioxide, MgO
Aluminium Oxide, MgO, Silicon Dioxide
Types of Metamorphism
Not Applicable
Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Coastal Erosion, Sea Erosion, Water Erosion
Grain Size
Medium to Fine Coarse Grained
Fine to Medium Grained
Fracture
Conchoidal
Conchoidal
Streak
White
Bluish Black
Porosity
Highly Porous
Less Porous
Luster
Shiny
Grainy, Pearly and Vitreous
Cleavage
Slaty
Not Available
Toughness
1.5
Not Available
Specific Gravity
2.5-2.9
Not Available
Transparency
Opaque
Opaque
Density
2.8-2.9 g/cm3
Not Available
Resistance
Impact Resistant, Pressure Resistant, Water Resistant
Heat Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
Afghanistan, Bangladesh, Bhutan, China, India, Japan, Kazakhstan, Malaysia, Pakistan, Russia, Thailand, Turkey, Vietnam
India, Russia
Africa
Egypt, Ethiopia, Morocco, Nigeria, South Africa
Ethiopia, Somalia, South Africa
Europe
Austria, England, France, Georgia, Germany, Italy, Liechtenstein, Monaco, Norway, Slovenia, Spain, Sweden, Switzerland
Iceland
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
Canada, Costa Rica, Cuba, Mexico, Panama, USA
Canada, USA
South America
Brazil, Colombia, Guyana
Brazil
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Queensland
Not Yet Found