Definition
Anthracite is a type of sedimentary rock which is hard and is variety of coal that has high luster
  
Comendite is a hard, peralkaline igneous rock, a type of light blue grey rhyolite
  
History
  
  
Origin
Pennsylvania, U.S.
  
Italy
  
Discoverer
Unknown
  
Unknown
  
Etymology
From Greek anthrakites, from anthrax, anthrak meaning coal
  
Comendite derives its name from the area of Le Commende on San Pietro Island in Italy
  
Class
Metamorphic Rocks
  
Igneous Rocks
  
Sub-Class
Durable Rock, Soft Rock
  
Durable Rock, Hard Rock
  
Family
  
  
Group
Not Applicable
  
Volcanic
  
Other Categories
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
  
Medium Grained Rock, Opaque Rock
  
Texture
Amorphous, Glassy
  
Porphyritic
  
Color
Black, Brown, Dark Brown, Grey, Light to Dark Grey
  
Blue, Bluish - Grey
  
Maintenance
Less
  
Less
  
Durability
Durable
  
Durable
  
Water Resistant
No
  
Yes
  
Scratch Resistant
No
  
Yes
  
Stain Resistant
No
  
Yes
  
Wind Resistant
No
  
Yes
  
Acid Resistant
No
  
Yes
  
Appearance
Veined or Pebbled
  
Foliated
  
Architecture
  
  
Interior Uses
Not Yet Used
  
Countertops, Decorative Aggregates, Interior Decoration
  
Exterior Uses
Not Yet Used
  
As Building Stone, As Facing Stone, Garden Decoration
  
Other Architectural Uses
Not Yet Used
  
Curbing
  
Industry
  
  
Construction Industry
Cement Manufacture, for Road Aggregate, Making natural cement, Steel Production
  
Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate, Landscaping, Making natural cement, Raw material for the manufacture of mortar
  
Medical Industry
In Chemical and Pharmaceutical Industry, Manufacture of Aspirins
  
Not Yet Used
  
Antiquity Uses
Not Yet Used
  
Artifacts
  
Other Uses
  
  
Commercial Uses
Alumina Refineries, Electricity Generation, Liquid Fuel, Manufacture of Soap, Solvents, Dyes, Plastics and Fibres, Paper Industry
  
Cemetery Markers
  
Types
Semi-anthracite and Meta-anthracite
  
Rhyolite
  
Features
Helps in production of Heat and Electricity, Used as fossil fuel
  
Very fine grained rock, It is One of the Oldest, Strongest and Hardest Rock
  
Archaeological Significance
  
  
Monuments
Not Yet Used
  
Not Yet Used
  
Famous Monuments
Not Applicable
  
Not Applicable
  
Sculpture
Not Yet Used
  
Not Yet Used
  
Famous Sculptures
Not Applicable
  
Not Applicable
  
Pictographs
Used
  
Not Used
  
Petroglyphs
Used
  
Not 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.
  
Comendite is a type of Igneous rock which is formed due to cooling and solidification of lava or magma. It may form with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.
  
Composition
  
  
Mineral Content
Calcite, Clay, Clay Minerals
  
Albite, Amphibole, Quartz
  
Compound Content
Carbon, Hydrogen, Nitrogen, Oxygen, Sulphur
  
Al, Fe, Potassium Oxide
  
Transformation
  
  
Metamorphism
Yes
  
Yes
  
Types of Metamorphism
Burial Metamorphism, Contact Metamorphism, Regional Metamorphism
  
Cataclastic Metamorphism, Regional Metamorphism
  
Weathering
No
  
Yes
  
Types of Weathering
Not Applicable
  
Biological Weathering, Chemical Weathering, Mechanical Weathering
  
Erosion
No
  
Yes
  
Types of Erosion
Not Applicable
  
Coastal Erosion, Water Erosion
  
Physical Properties
  
  
Hardness
1-1.5
  
6-7
  
Grain Size
Medium to Fine Coarse Grained
  
Medium Grained
  
Fracture
Conchoidal
  
Pervasive
  
Streak
Black
  
Bluish Black
  
Porosity
Less Porous
  
Highly Porous
  
Luster
Shiny
  
Dull
  
Compressive Strength
Not Available
  
92.40 N/mm
2
  
21
Cleavage
Non-Existent
  
Not Available
  
Toughness
Not Available
  
2
  
Specific Gravity
1.1-1.4
  
2.38
  
Transparency
Opaque
  
Opaque
  
Density
1.25-2.5 g/cm3
  
Not Available
  
Thermal Properties
  
  
Specific Heat Capacity
1.32 kJ/Kg K
  
4
Not Available
  
Resistance
Heat Resistant, Water Resistant
  
Heat Resistant, Impact Resistant
  
Deposits in Eastern Continents
  
  
Asia
Bangladesh, Burma, Cambodia, China, India, Indonesia, Kazakhstan, Malaysia, Mongolia, Pakistan, Turkey, Vietnam
  
China
  
Africa
Botswana, Kenya, Morocco, Mozambique, South Africa, Tanzania
  
East Africa
  
Europe
Belgium, Bulgaria, England, France, Germany, Greece, Hungary, Kosovo, Netherlands, Norway, Poland, Romania, Serbia, Slovakia, Slovenia, The Czech Republic, Ukraine, United Kingdom
  
Italy
  
Others
Not Yet Found
  
Not Yet Found
  
Deposits in Western Continents
  
  
North America
Canada, Mexico, USA
  
Not Yet Found
  
South America
Brazil, Chile, Colombia, Venezuela
  
Not Yet Found
  
Deposits in Oceania Continent
  
  
Australia
New South Wales, Queensland, Victoria
  
Queensland