Definition
Lignite is a soft brownish coal which shows traces of plants and is intermediate between bituminous coal and peat
Tephrite is an aphanitic to porphyritic textured, volcanic igneous rock
Discoverer
Unknown
Van Tooren
Etymology
From French, Latin lignum wood + -ite1
From Greek tephra, ashes from Indo-European base, to burn
Class
Sedimentary Rocks
Igneous Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Hard Rock
Other Categories
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Amorphous, Glassy
Aphanitic to Porphyritic
Color
Black, Brown, Dark Brown, Grey, Light to Dark Grey
Black, Brown, Green, Grey, White
Durability
Durable
Durable
Appearance
Veined or Pebbled
Vesicular
Interior Uses
-
Decorative Aggregates, Flooring, Homes, Interior Decoration
Exterior Uses
-
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings
Other Architectural Uses
-
Curbing
Construction Industry
for Road Aggregate, Steel Production
Landscaping
Antiquity Uses
-
Artifacts, Sculpture
Commercial Uses
Electricity Generation
Production of Lime, Soil Conditioner
Types
Xyloid Lignite or Fossil Wood and Compact Lignite or Perfect Lignite
Igneous rock
Features
Generally rough to touch, Helps in production of Heat and Electricity, Used as fossil fuel
Host Rock for Lead
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.
Tephrite is a fine-grained, hard rock which is a type of metasomatite, essentially altered basalt. It forms with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.
Mineral Content
-
Alkali feldspar, Nepheline, Plagioclase, Pyroxene
Compound Content
Carbon, Hydrogen, Nitrogen, Oxygen, Sulphur
CaO, Carbon Dioxide, MgO, Silicon Dioxide
Types of Metamorphism
-
Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion, Water Erosion, Wind Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion
Grain Size
Medium to Fine Coarse Grained
Medium to Fine Coarse Grained
Fracture
Conchoidal
Uneven
Streak
Black
Bluish Black
Porosity
Highly Porous
Very Less Porous
Luster
Dull to Vitreous to Submetallic
Subvitreous to Dull
Cleavage
-
Crenulation and Pervasive
Specific Gravity
1.1-1.4
2.86
Transparency
Opaque
Opaque
Density
800-801 g/cm3
2.8-2.9 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
-
Africa
Botswana, Kenya, Morocco, Mozambique, South Africa, Tanzania
Namibia, Uganda
Europe
Belgium, Bulgaria, England, France, Germany, Greece, Hungary, Kosovo, Netherlands, Norway, Poland, Romania, Serbia, Slovakia, Slovenia, The Czech Republic, Ukraine, United Kingdom
Germany, Hungary, Italy, Portugal, Spain
Deposits in Western Continents
North America
Canada, Mexico, USA
USA
South America
Brazil, Chile, Colombia, Venezuela
-
Deposits in Oceania Continent
Australia
New South Wales, Queensland, Victoria
New Zealand, Western Australia