Definition
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
Slate is a fine-grained, foliated, homogeneous metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade regional metamorphism
History
Origin
Adak, Aleutian Islands
England
Discoverer
Defant and Drummond
Abraham Gottlob Werner
Etymology
From Adak, Aleutian Islands
From Old French esclate, from esclat (French éclat)
Class
Igneous Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Medium Hardness Rock
Family
Group
Volcanic
-
Other Categories
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Porphyritic
Foliated
Color
Black, Brown, Light to Dark Grey
Black, Brown, Buff, Green, Light to Dark Grey, Purple, Red, Shades of Blue
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Dull and Soft
Dull
Architecture
Interior Uses
Decorative Aggregates, Floor Tiles, Homes, Hotels, Kitchens
Bathrooms, Decorative Aggregates, Entryways, Floor Tiles, Flooring, Homes, Hotels, Interior Decoration, Kitchens, Stair Treads
Exterior Uses
As Building Stone, As Facing Stone, Office Buildings
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
Other Architectural Uses
Whetstones
Curbing
Industry
Construction Industry
As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone
As Dimension Stone
Medical Industry
-
-
Antiquity Uses
Monuments, Sculpture, Small Figurines
Artifacts, Monuments, Sculpture, Small Figurines
Other Uses
Commercial Uses
Commemorative Tablets, Pottery, Used in aquariums
Blackboards, Commemorative Tablets, Laboratory bench tops, Standard material for the bed of Billiard table, Standard material for the beds of Pool and Snooker table, Tombstones, Used in aquariums, Writing Slates
Types
Intermediate volcanic rock
Phyllite, Schist, and Slate
Features
Has High structural resistance against erosion and climate, Host rock for Diamond, Very fine grained rock
Easily splits into thin plates, Surfaces are often shiny, Very fine grained rock
Archaeological Significance
Monuments
-
-
Famous Monuments
-
-
Sculpture
-
-
Famous Sculptures
-
-
Pictographs
-
-
Petroglyphs
-
-
Figurines
-
-
Fossils
Absent
Absent
Formation
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.
Slate is a low grade metamorphic rock that is generally formed by metamorphosis of mudstone or shale, under relatively low pressure and temperature conditions.
Composition
Mineral Content
Olivine, Plagioclase, Pyroxene
Apatite, Biotite, Chlorite, Feldspar, Graphite, Hematite, Kaolinite, Magnetite, Pyrite, Tourmaline, Zircon
Compound Content
Aluminium Oxide, MgO, Silicon Dioxide
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Titanium Dioxide
Transformation
Metamorphism
✔
✘
✔
✘
Types of Metamorphism
Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism
Weathering
✔
✘
✔
✘
Types of Weathering
Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Erosion
✔
✘
✔
✘
Types of Erosion
Coastal Erosion, Sea Erosion, Water Erosion
Coastal Erosion, Glacier Erosion, Water Erosion, Wind Erosion
Physical Properties
Hardness
3-43-4
1
7
👆🏻
Grain Size
Fine to Medium Grained
Very fine-grained
Fracture
Conchoidal
Splintery
Streak
Bluish Black
Light to dark brown
Porosity
Less Porous
Less Porous
Luster
Grainy, Pearly and Vitreous
Dull
Compressive Strength
200.00 N/mm230.00 N/mm2
0.15
450
👆🏻
Cleavage
-
Slaty
Toughness
-
1.2
Specific Gravity
-99992.65-2.8
0
8.4
👆🏻
Transparency
Opaque
Opaque
Density
-9999 g/cm32.6-2.8 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
0.84 kJ/Kg K0.76 kJ/Kg K
0.14
3.2
👆🏻
Resistance
Heat Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
India, Russia
China, India, Turkey
Africa
Ethiopia, Somalia, South Africa
-
Europe
Iceland
Belgium, France, Germany, Italy, Norway, Portugal, Spain, United Kingdom
Others
-
Arctic
Deposits in Western Continents
North America
Canada, USA
USA
South America
Brazil
Brazil
Deposits in Oceania Continent
Australia
-
-