Definition
Adakite is an intermediate to felsic volcanic rock that has geochemical characteristics of magma which is said to be formed by partial melting of altered basalt that is subducted below volcanic arcs
Lignite is a soft brownish coal which shows traces of plants and is intermediate between bituminous coal and peat
Origin
Adak, Aleutian Islands
France
Discoverer
Defant and Drummond
Unknown
Etymology
From Adak, Aleutian Islands
From French, Latin lignum wood + -ite1
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Soft Rock
Other Categories
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Porphyritic
Amorphous, Glassy
Color
Black, Brown, Light to Dark Grey
Black, Brown, Dark Brown, Grey, Light to Dark Grey
Durability
Durable
Durable
Appearance
Dull and Soft
Veined or Pebbled
Interior Uses
Decorative Aggregates, Floor Tiles, Homes, Hotels, Kitchens
-
Exterior Uses
As Building Stone, As Facing Stone, Office Buildings
-
Other Architectural Uses
Whetstones
-
Construction Industry
As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone
for Road Aggregate, Steel Production
Antiquity Uses
Monuments, Sculpture, Small Figurines
-
Commercial Uses
Commemorative Tablets, Pottery, Used in aquariums
Electricity Generation
Types
Intermediate volcanic rock
Xyloid Lignite or Fossil Wood and Compact Lignite or Perfect Lignite
Features
Has High structural resistance against erosion and climate, Host rock for Diamond, Very fine grained rock
Generally rough to touch, Helps in production of Heat and Electricity, Used as fossil fuel
Archaeological Significance
Formation
Adakite rocks are formed when the hydrous fluids are released from minerals that break down in metamorphosed basalt, and rise into the mantle they initiate partial melting.
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.
Mineral Content
Olivine, Plagioclase, Pyroxene
-
Compound Content
Aluminium Oxide, MgO, Silicon Dioxide
Carbon, Hydrogen, Nitrogen, Oxygen, Sulphur
Types of Metamorphism
Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism
-
Types of Weathering
Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Coastal Erosion, Sea Erosion, Water Erosion
Chemical Erosion, Water Erosion, Wind Erosion
Grain Size
Fine to Medium Grained
Medium to Fine Coarse Grained
Fracture
Conchoidal
Conchoidal
Streak
Bluish Black
Black
Porosity
Less Porous
Highly Porous
Luster
Grainy, Pearly and Vitreous
Dull to Vitreous to Submetallic
Specific Gravity
-9999
1.1-1.4
Transparency
Opaque
Opaque
Density
-9999 g/cm3
800-801 g/cm3
Resistance
Heat Resistant, Pressure Resistant, Wear Resistant
Heat Resistant
Deposits in Eastern Continents
Asia
India, Russia
Bangladesh, Burma, Cambodia, China, India, Indonesia, Kazakhstan, Malaysia, Mongolia, Pakistan, Turkey, Vietnam
Africa
Ethiopia, Somalia, South Africa
Botswana, Kenya, Morocco, Mozambique, South Africa, Tanzania
Europe
Iceland
Belgium, Bulgaria, England, France, Germany, Greece, Hungary, Kosovo, Netherlands, Norway, Poland, Romania, Serbia, Slovakia, Slovenia, The Czech Republic, Ukraine, United Kingdom
Deposits in Western Continents
North America
Canada, USA
Canada, Mexico, USA
South America
Brazil
Brazil, Chile, Colombia, Venezuela
Deposits in Oceania Continent
Australia
-
New South Wales, Queensland, Victoria