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
Anthracite is a type of sedimentary rock which is hard and is variety of coal that has high luster
History
Origin
England
Pennsylvania, U.S.
Discoverer
Abraham Gottlob Werner
Unknown
Etymology
From Old French esclate, from esclat (French éclat)
From Greek anthrakites, from anthrax, anthrak meaning coal
Class
Metamorphic Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Soft Rock
Family
Group
-
-
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Foliated
Amorphous, Glassy
Color
Black, Brown, Buff, Green, Light to Dark Grey, Purple, Red, Shades of Blue
Black, Brown, Dark Brown, Grey, Light to Dark Grey
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Dull
Veined or Pebbled
Architecture
Interior Uses
Bathrooms, Decorative Aggregates, Entryways, Floor Tiles, Flooring, Homes, Hotels, Interior Decoration, Kitchens, Stair Treads
-
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
-
Other Architectural Uses
Curbing
-
Industry
Construction Industry
As Dimension Stone
Cement Manufacture, for Road Aggregate, Making natural cement, Steel Production
Medical Industry
-
In Chemical and Pharmaceutical Industry, Manufacture of Aspirins
Antiquity Uses
Artifacts, Monuments, 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
Alumina Refineries, Electricity Generation, Liquid Fuel, Manufacture of Soap, Solvents, Dyes, Plastics and Fibres, Paper Industry
Types
Phyllite, Schist, and Slate
Semi-anthracite and Meta-anthracite
Features
Easily splits into thin plates, Surfaces are often shiny, Very fine grained rock
Helps in production of Heat and Electricity, Used as fossil fuel
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.
Anthracite forms from the accumulation of plant debris in a swamp environment. When plant debris dies and falls into the swamp, the standing water of the swamp protects it from decay.
Composition
Mineral Content
Apatite, Biotite, Chlorite, Feldspar, Graphite, Hematite, Kaolinite, Magnetite, Pyrite, Tourmaline, Zircon
Calcite, Clay, Clay Minerals
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Titanium Dioxide
Carbon, Hydrogen, Nitrogen, Oxygen, Sulphur
Transformation
Metamorphism
✔
✘
✔
✘
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism
Burial Metamorphism, Contact Metamorphism, Regional Metamorphism
Weathering
✔
✘
✔
✘
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
-
Erosion
✔
✘
✔
✘
Types of Erosion
Coastal Erosion, Glacier Erosion, Water Erosion, Wind Erosion
-
Physical Properties
Hardness
3-41-1.5
1
7
👆🏻
Grain Size
Very fine-grained
Medium to Fine Coarse Grained
Fracture
Splintery
Conchoidal
Streak
Light to dark brown
Black
Porosity
Less Porous
Less Porous
Luster
Dull
Shiny
Compressive Strength
30.00 N/mm2-
0.15
450
👆🏻
Cleavage
Slaty
-
Toughness
1.2
-
Specific Gravity
2.65-2.81.1-1.4
0
8.4
👆🏻
Transparency
Opaque
Opaque
Density
2.6-2.8 g/cm31.25-2.5 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
0.76 kJ/Kg K1.32 kJ/Kg K
0.14
3.2
👆🏻
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Water Resistant
Deposits in Eastern Continents
Asia
China, India, Turkey
Bangladesh, Burma, Cambodia, China, India, Indonesia, Kazakhstan, Malaysia, Mongolia, Pakistan, Turkey, Vietnam
Africa
-
Botswana, Kenya, Morocco, Mozambique, South Africa, Tanzania
Europe
Belgium, France, Germany, Italy, Norway, Portugal, Spain, United Kingdom
Belgium, Bulgaria, England, France, Germany, Greece, Hungary, Kosovo, Netherlands, Norway, Poland, Romania, Serbia, Slovakia, Slovenia, The Czech Republic, Ukraine, United Kingdom
Others
Arctic
-
Deposits in Western Continents
North America
USA
Canada, Mexico, USA
South America
Brazil
Brazil, Chile, Colombia, Venezuela
Deposits in Oceania Continent
Australia
-
New South Wales, Queensland, Victoria