Definition
Very fine grained fault rock which is composed of glassy matrix that often contains inclusions of wall-rock fragments.
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
Origin
USA
Adak, Aleutian Islands
Discoverer
Unknown
Defant and Drummond
Etymology
From pseudo- + tachylite, a glassy rock generated by frictional heat within faults.
From Adak, Aleutian Islands
Class
Metamorphic Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Group
Not Applicable
Volcanic
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Quench
Porphyritic
Color
Black, Brown, Colourless, Green, Grey, Pink, White
Black, Brown, Light to Dark Grey
Durability
Durable
Durable
Appearance
Dull and Soft
Dull and Soft
Interior Uses
Decorative Aggregates, Entryways, Interior Decoration
Decorative Aggregates, Floor Tiles, Homes, Hotels, Kitchens
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration
As Building Stone, As Facing Stone, Office Buildings
Other Architectural Uses
Curbing
Whetstones
Construction Industry
As Dimension Stone, Cement Manufacture, for Road Aggregate, Making natural cement
As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Monuments
Monuments, Sculpture, Small Figurines
Commercial Uses
Creating Artwork, Gemstone
Commemorative Tablets, Pottery, Used in aquariums
Types
Not Available
Not Available
Features
Host Rock for Lead
Has High structural resistance against erosion and climate, Host rock for Diamond, Very fine grained rock
Archaeological Significance
Famous Monuments
Data Not Available
Data Not Available
Sculpture
Not Yet Used
Used
Famous Sculptures
Not Applicable
Data Not Available
Pictographs
Not Used
Used
Petroglyphs
Not Used
Used
Figurines
Not Yet Used
Used
Formation
Due to change in environmental conditions, rocks are heated and pressurized deep inside the Earth's surface. Pseudotachylite is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.
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.
Mineral Content
Iron Oxides, Pyroxene, Quartz, Stishovite, Sulfides
Olivine, Plagioclase, Pyroxene
Compound Content
Carbon Dioxide, Silicon Dioxide, Sulfur Dioxide, Sulphur
Aluminium Oxide, MgO, Silicon Dioxide
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism
Types of Weathering
Not Applicable
Chemical Weathering, Mechanical Weathering
Types of Erosion
Not Applicable
Coastal Erosion, Sea Erosion, Water Erosion
Grain Size
Very fine-grained
Fine to Medium Grained
Fracture
Uneven
Conchoidal
Streak
Light to dark brown
Bluish Black
Porosity
Less Porous
Less Porous
Luster
Vitreous
Grainy, Pearly and Vitreous
Compressive Strength
Not Available
Cleavage
Irregular
Not Available
Toughness
Not Available
Not Available
Specific Gravity
2.46-2.86
Not Available
Transparency
Transparent to Translucent
Opaque
Density
2.7-2.9 g/cm3
Not Available
Specific Heat Capacity
Not Available
Resistance
Heat Resistant
Heat Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
South Korea
India, Russia
Africa
Western Africa
Ethiopia, Somalia, South Africa
Europe
Great Britain, Switzerland
Iceland
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
Not Yet Found
Canada, USA
South America
Not Yet Found
Brazil
Deposits in Oceania Continent
Australia
Central Australia, Western Australia
Not Yet Found
All about Pseudotachylite and Adakite Properties
Know all about Pseudotachylite and Adakite properties here. All properties of rocks are important as they define the type of rock and its application. Pseudotachylite belongs to Metamorphic Rocks while Adakite belongs to Igneous Rocks.Texture of Pseudotachylite is Quench whereas that of Adakite is Porphyritic. Pseudotachylite appears Dull and Soft and Adakite appears Dull and Soft. The luster of Pseudotachylite is vitreous while that of Adakite is grainy, pearly and vitreous. Pseudotachylite is available in black, brown, colourless, green, grey, pink, white colors whereas Adakite is available in black, brown, light to dark grey colors. The commercial uses of Pseudotachylite are creating artwork, gemstone and that of Adakite are commemorative tablets, pottery, used in aquariums.