Definition
Lignite is a soft brownish coal which shows traces of plants and is intermediate between bituminous coal and peat
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
Origin
France
New Zealand
Discoverer
Unknown
Unknown
Etymology
From French, Latin lignum wood + -ite1
From German which means hornstone
Class
Sedimentary Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Soft Rock
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
Durability
Durable
Durable
Appearance
Veined or Pebbled
Dull
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
Construction Industry
for Road Aggregate, Steel Production
for Road Aggregate, Roadstone
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Not Yet Used
Artifacts, Monuments
Commercial Uses
Electricity Generation
Cemetery Markers, Commemorative Tablets, Creating Artwork
Types
Xyloid Lignite or Fossil Wood and Compact Lignite or Perfect Lignite
Biotite hornfels
Features
Generally rough to touch, 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
Figurines
Not Yet Used
Not Yet Used
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.
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.
Mineral Content
Not Available
Andalusite
Compound Content
Carbon, Hydrogen, Nitrogen, Oxygen, Sulphur
Fe, Mg
Types of Metamorphism
Not Applicable
Not Applicable
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering
Types of Erosion
Chemical Erosion, Water Erosion, Wind Erosion
Chemical Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Grain Size
Medium to Fine Coarse Grained
Fine Grained
Fracture
Conchoidal
Conchoidal
Porosity
Highly Porous
Highly Porous
Luster
Dull to Vitreous to Submetallic
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
800-801 g/cm3
0.25-0.30 g/cm3
Resistance
Heat 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
Lignite vs Hornfels Characteristics
Though some rocks look identical, they have certain characteristics which distinguish them from others. Characteristics of rocks include texture, appearance, color, fracture, streak, hardness etc. Lignite vs Hornfels characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Lignite and Properties of Hornfels. Learn more about Lignite vs Hornfels in the next section. The interior uses of Lignite include Not yet used whereas the interior uses of Hornfels include Decorative aggregates, Flooring, Homes and Interior decoration. Due to some exceptional properties of Lignite and Hornfels, they have various applications in construction industry. The uses of Lignite in construction industry include For road aggregate, Steel production and that of Hornfels include For road aggregate, Roadstone.
More about Lignite and Hornfels
Here you can know more about Lignite and Hornfels. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Lignite and Hornfels consists of mineral content and compound content. The mineral content of Lignite is not available and mineral content of Hornfels includes Andalusite. You can also check out the list of all Sedimentary Rocks. When we have to compare Lignite vs Hornfels, the texture, color and appearance plays an important role in determining the type of rock. Lignite is available in black, brown, dark brown, grey, light to dark grey colors whereas, Hornfels is available in brown, dark greenish - grey, green, reddish brown colors. Appearance of Lignite is Veined or Pebbled and that of Hornfels is Dull. Properties of rock is another aspect for Lignite vs Hornfels. The hardness of Lignite is 1 and that of Hornfels is 2-3. The types of Lignite are Xyloid Lignite or Fossil Wood and Compact Lignite or Perfect Lignite whereas types of Hornfels are Biotite hornfels. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Lignite is black while that of Hornfels is unknown. The specific heat capacity of Lignite is 1.26 kJ/Kg K and that of Hornfels is 0.84 kJ/Kg K. Depending on the properties like hardness, toughness, specific heat capacity, porosity etc., rocks are resistant to heat, wear, impact, etc.Lignite is heat resistant whereas Hornfels is heat resistant, impact resistant, pressure resistant.