Definition
Anthracite is a type of sedimentary rock which is hard and is variety of coal that has high luster
  
Hornfels is a metamorphic rock formed by the contact between mudstone or other clay rich rock, and a hot igneous body, and represents a heat altered equivalent of the original rock
  
History
  
  
Origin
Pennsylvania, U.S.
  
New Zealand
  
Discoverer
Unknown
  
Unknown
  
Etymology
From Greek anthrakites, from anthrax, anthrak meaning coal
  
From German which means hornstone
  
Class
Metamorphic Rocks
  
Metamorphic Rocks
  
Sub-Class
Durable Rock, Soft Rock
  
Durable Rock, Soft 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
Amorphous, Glassy
  
Granular, Platy
  
Color
Black, Brown, Dark Brown, Grey, Light to Dark Grey
  
Brown, Dark Greenish - Grey, Green, Reddish Brown
  
Maintenance
Less
  
Less
  
Durability
Durable
  
Durable
  
Water Resistant
No
  
Yes
  
Scratch Resistant
No
  
No
  
Stain Resistant
No
  
No
  
Wind Resistant
No
  
No
  
Acid Resistant
No
  
No
  
Appearance
Veined or Pebbled
  
Dull
  
Architecture
  
  
Interior Uses
Not Yet Used
  
Decorative Aggregates, Flooring, Homes, Interior Decoration
  
Exterior Uses
Not Yet Used
  
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
  
Other Architectural Uses
Not Yet Used
  
Curbing
  
Industry
  
  
Construction Industry
Cement Manufacture, for Road Aggregate, Making natural cement, Steel Production
  
for Road Aggregate, Roadstone
  
Medical Industry
In Chemical and Pharmaceutical Industry, Manufacture of Aspirins
  
Not Yet Used
  
Antiquity Uses
Not Yet Used
  
Artifacts, Monuments
  
Other Uses
  
  
Commercial Uses
Alumina Refineries, Electricity Generation, Liquid Fuel, Manufacture of Soap, Solvents, Dyes, Plastics and Fibres, Paper Industry
  
Cemetery Markers, Commemorative Tablets, Creating Artwork
  
Types
Semi-anthracite and Meta-anthracite
  
Biotite hornfels
  
Features
Helps in production of Heat and Electricity, Used as fossil fuel
  
Smooth to touch
  
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
  
Used
  
Petroglyphs
Used
  
Used
  
Figurines
Not Yet Used
  
Not Yet Used
  
Fossils
Absent
  
Absent
  
Formation
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.
  
Due to change in environmental conditions, rocks are heated and pressurized deep inside the Earth's surface. Hornfels is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.
  
Composition
  
  
Mineral Content
Calcite, Clay, Clay Minerals
  
Andalusite
  
Compound Content
Carbon, Hydrogen, Nitrogen, Oxygen, Sulphur
  
Fe, Mg
  
Transformation
  
  
Metamorphism
Yes
  
No
  
Types of Metamorphism
Burial Metamorphism, Contact Metamorphism, Regional Metamorphism
  
Not Applicable
  
Weathering
No
  
Yes
  
Types of Weathering
Not Applicable
  
Biological Weathering
  
Erosion
No
  
Yes
  
Types of Erosion
Not Applicable
  
Chemical Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
  
Physical Properties
  
  
Hardness
1-1.5
  
2-3
  
Grain Size
Medium to Fine Coarse Grained
  
Fine Grained
  
Fracture
Conchoidal
  
Conchoidal
  
Streak
Black
  
Unknown
  
Porosity
Less Porous
  
Highly Porous
  
Luster
Shiny
  
Shiny
  
Compressive Strength
Not Available
  
Cleavage
Non-Existent
  
Perfect
  
Toughness
Not Available
  
Not Yet Found
  
Specific Gravity
1.1-1.4
  
3.4-3.9
  
Transparency
Opaque
  
Opaque
  
Density
1.25-2.5 g/cm3
  
0.25-0.30 g/cm3
  
Thermal Properties
  
  
Specific Heat Capacity
1.32 kJ/Kg K
  
4
0.84 kJ/Kg K
  
15
Resistance
Heat Resistant, Water Resistant
  
Heat Resistant, Impact Resistant, Pressure Resistant
  
Deposits in Eastern Continents
  
  
Asia
Bangladesh, Burma, Cambodia, China, India, Indonesia, Kazakhstan, Malaysia, Mongolia, Pakistan, Turkey, Vietnam
  
Bangladesh, Bhutan, China, India, North Korea, Qatar, Russia, Saudi Arabia, South Korea, Thailand
  
Africa
Botswana, Kenya, Morocco, Mozambique, South Africa, Tanzania
  
Cameroon, East Africa, Tanzania, Western Africa
  
Europe
Belgium, Bulgaria, England, France, Germany, Greece, Hungary, Kosovo, Netherlands, Norway, Poland, Romania, Serbia, Slovakia, Slovenia, The Czech Republic, Ukraine, United Kingdom
  
United Kingdom
  
Others
Not Yet Found
  
Not Yet Found
  
Deposits in Western Continents
  
  
North America
Canada, Mexico, USA
  
Canada, USA
  
South America
Brazil, Chile, Colombia, Venezuela
  
Bolivia, Brazil, Colombia, Ecuador
  
Deposits in Oceania Continent
  
  
Australia
New South Wales, Queensland, Victoria
  
New South Wales, New Zealand, Queensland, Western Australia