Definition
Lignite is a soft brownish coal which shows traces of plants and is intermediate between bituminous coal and peat
Argillites are highly compact sedimentary or slightly metamorphosed rocks that consist largely or wholly of particles of clay or silt but lack the fissility of shale or the cleavage characteristic of slate
Discoverer
Unknown
Unknown
Etymology
From French, Latin lignum wood + -ite1
From Latin Argilla (clay) and -ite in English which became agrilla+ -ite = Argillite
Class
Sedimentary Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Soft Rock
Other Categories
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Amorphous, Glassy
Clastic, Polished
Color
Black, Brown, Dark Brown, Grey, Light to Dark Grey
Dark Grey to Black, Pink, Red, White
Durability
Durable
Durable
Appearance
Veined or Pebbled
Rough and Dull
Interior Uses
-
Decorative Aggregates, Homes, Interior Decoration
Exterior Uses
-
As Building Stone, Garden Decoration, Office Buildings
Other Architectural Uses
-
Curbing, Whetstones
Construction Industry
for Road Aggregate, Steel Production
Used for flooring, stair treads, borders and window sills.
Antiquity Uses
-
Artifacts, Monuments, Sculpture
Commercial Uses
Electricity Generation
Fire resistant, Used to manufracture paperweights and bookends
Types
Xyloid Lignite or Fossil Wood and Compact Lignite or Perfect Lignite
Metamorphic rock
Features
Generally rough to touch, Helps in production of Heat and Electricity, Used as fossil fuel
Is one of the oldest rock
Archaeological Significance
Formation
Coal formation takes place due to accumulation of plant debris in a swamp environment. The Coal formation process continues, as peat turns into lignite brown or black coal at increasing heat and pressure.
An argillite is a fine-grained sedimentary rock mainly composed of clay particles which forms from lithified muds which contain variable amounts of silt-sized particles.
Mineral Content
-
Biotite, Chlorite, Feldspar, Micas, Muscovite or Illite, Plagioclase, Pyrite, Quartz
Compound Content
Carbon, Hydrogen, Nitrogen, Oxygen, Sulphur
Iron(III) Oxide, Potassium Oxide, MgO, Silicon Dioxide
Types of Metamorphism
-
-
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering
Types of Erosion
Chemical Erosion, Water Erosion, Wind Erosion
Chemical Erosion
Grain Size
Medium to Fine Coarse Grained
Fine Grained
Fracture
Conchoidal
Conchoidal to Uneven
Streak
Black
White to Grey
Porosity
Highly Porous
Highly Porous
Luster
Dull to Vitreous to Submetallic
Waxy and Dull
Specific Gravity
1.1-1.4
2.56-2.68
Transparency
Opaque
Opaque
Density
800-801 g/cm3
2.54-2.66 g/cm3
Resistance
Heat Resistant
Heat Resistant, Impact Resistant
Deposits in Eastern Continents
Asia
Bangladesh, Burma, Cambodia, China, India, Indonesia, Kazakhstan, Malaysia, Mongolia, Pakistan, Turkey, Vietnam
Bangladesh, China, India, Russia
Africa
Botswana, Kenya, Morocco, Mozambique, South Africa, Tanzania
Ethiopia, Kenya, Morocco, South Africa, Tanzania
Europe
Belgium, Bulgaria, England, France, Germany, Greece, Hungary, Kosovo, Netherlands, Norway, Poland, Romania, Serbia, Slovakia, Slovenia, The Czech Republic, Ukraine, United Kingdom
Austria, France, Germany, Greece, Italy, Romania, Scotland, Spain, Switzerland
Deposits in Western Continents
North America
Canada, Mexico, USA
USA
South America
Brazil, Chile, Colombia, Venezuela
Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Deposits in Oceania Continent
Australia
New South Wales, Queensland, Victoria
New South Wales, New Zealand, Queensland, Victoria, Western Australia