Definition
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
Amphibolite can be defined as a granular metamorphic rock which mainly consist of hornblende and plagioclase
History
Origin
England
-
Discoverer
Abraham Gottlob Werner
Alexandre Brongniart
Etymology
From Old French esclate, from esclat (French éclat)
From Amphibole + -ite
Class
Metamorphic Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Family
Group
-
-
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Foliated
Banded, Foliated, Massive
Color
Black, Brown, Buff, Green, Light to Dark Grey, Purple, Red, Shades of Blue
Black, Brown, Green, Grey
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Dull
Foliated
Architecture
Interior Uses
Bathrooms, Decorative Aggregates, Entryways, Floor Tiles, Flooring, Homes, Hotels, Interior Decoration, Kitchens, Stair Treads
Countertops, Decorative Aggregates, Entryways, Floor Tiles, Flooring, Homes, Hotels, Kitchens
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
As Building Stone, As Facing Stone, Paving Stone, Office Buildings
Other Architectural Uses
Curbing
Curbing
Industry
Construction Industry
As Dimension Stone
As Dimension Stone, Building houses or walls, Cobblestones, Construction Aggregate, for Road Aggregate, Landscaping, Production of Glass and Ceramics, Roadstone
Medical Industry
-
-
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
Artifacts, Sculpture, Small Figurines
Other Uses
Commercial Uses
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
Cemetery Markers, Commemorative Tablets, Creating Artwork
Types
Phyllite, Schist, and Slate
Hornblendite
Features
Easily splits into thin plates, Surfaces are often shiny, Very fine grained rock
Clasts are smooth to touch, Matrix variable, Surfaces are often shiny
Archaeological Significance
Monuments
-
-
Famous Monuments
-
-
Sculpture
-
-
Famous Sculptures
-
-
Pictographs
-
-
Petroglyphs
-
-
Figurines
-
-
Fossils
Absent
Absent
Formation
Slate is a low grade metamorphic rock that is generally formed by metamorphosis of mudstone or shale, under relatively low pressure and temperature conditions.
Amphibolite is a coarse-grained metamorphic rock which forms by metamorphism of mafic igneous rocks like basalt and gabbro or from the metamorphism of clay-rich sedimentary rocks like marl or graywacke.
Composition
Mineral Content
Apatite, Biotite, Chlorite, Feldspar, Graphite, Hematite, Kaolinite, Magnetite, Pyrite, Tourmaline, Zircon
Amphibole, Andalusite, Biotite, Calcite, Epidote, Garnet, Hornblade, Kyanite, Magnetite, Olivine, Plagioclase, Pyroxene, Staurolite, Wollastonite
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Titanium Dioxide
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Transformation
Metamorphism
✔
✘
✔
✘
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism
-
Weathering
✔
✘
✔
✘
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Chemical Weathering, Mechanical Weathering
Erosion
✔
✘
✔
✘
Types of Erosion
Coastal Erosion, Glacier Erosion, Water Erosion, Wind Erosion
Chemical Erosion, Glacier Erosion, Sea Erosion, Wind Erosion
Physical Properties
Hardness
3-46-7
1
7
👆🏻
Grain Size
Very fine-grained
Medium to Coarse Grained
Fracture
Splintery
Irregular to Conchoidal
Streak
Light to dark brown
White to Grey
Porosity
Less Porous
Less Porous
Luster
Dull
Vitreous to Dull
Compressive Strength
30.00 N/mm290.00 N/mm2
0.15
450
👆🏻
Cleavage
Slaty
-
Toughness
1.2
2.3
Specific Gravity
2.65-2.82.5
0
8.4
👆🏻
Transparency
Opaque
Opaque
Density
2.6-2.8 g/cm32.85-3.07 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
0.76 kJ/Kg K0.84 kJ/Kg K
0.14
3.2
👆🏻
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
China, India, Turkey
Russia, Turkey
Africa
-
Burundi, Djibouti, Eritrea, Ethiopia, Kenya, Madagascar, Rwanda, Somalia, South Africa, Sudan, Tanzania, Uganda
Europe
Belgium, France, Germany, Italy, Norway, Portugal, Spain, United Kingdom
Germany, Greece, Iceland, Norway, Poland
Others
Arctic
-
Deposits in Western Continents
North America
USA
Canada, USA
South America
Brazil
Brazil
Deposits in Oceania Continent
Australia
-
South Australia, Western Australia