Definition
Very fine grained fault rock which is composed of glassy matrix that often contains inclusions of wall-rock fragments.
Blueschist is a metamorphic rock which is generally blue in color and is formed under conditions of high pressure and low temperature
Discoverer
Unknown
Edgar Bailey
Etymology
From pseudo- + tachylite, a glassy rock generated by frictional heat within faults.
From French schiste, Greek skhistos i.e. split
Class
Metamorphic Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Color
Black, Brown, Green, Grey, Pink, White
Blue, Bluish - Grey, Purple, Shades of Blue
Durability
Durable
Durable
Appearance
Dull and Soft
Dull and Banded
Interior Uses
Decorative Aggregates, Entryways, Interior Decoration
Floor Tiles, Flooring, Homes, Hotels, Kitchens
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration
Garden Decoration, Office Buildings
Other Architectural Uses
Curbing
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Construction Industry
As Dimension Stone, Cement Manufacture, for Road Aggregate, Making natural cement
As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone
Antiquity Uses
Artifacts, Monuments
Artifacts, Monuments, Sculpture
Commercial Uses
Creating Artwork, Gemstone
Cemetery Markers, Commemorative Tablets, Creating Artwork, Curling, Tombstones
Types
Cataclastic rock
Metamorphic rock
Features
Host Rock for Lead
Has High structural resistance against erosion and climate, Very fine grained rock
Archaeological Significance
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.
Blueschist forms due to the metamorphism of basalt and other rocks with similar composition at high pressures and low temperatures and approximately corresponding to a depth of 15 to 30 kilometers and 200 to 500 °C.
Mineral Content
Iron Oxides, Pyroxene, Quartz, Stishovite, Sulfides
Albite, Chlorite, Epidote, Garnet, Glaucophane, Lawsonite, Muscovite or Illite, Quartz
Compound Content
Carbon Dioxide, Silicon Dioxide, Sulfur Dioxide, Sulphur
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
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Types of Weathering
-
Mechanical Weathering
Types of Erosion
-
Chemical Erosion, Coastal Erosion, Water Erosion, Wind Erosion
Grain Size
Very fine-grained
Fine to Medium Grained
Fracture
Uneven
Conchoidal
Streak
Light to dark brown
White to Grey
Porosity
Less Porous
Highly Porous
Specific Gravity
2.46-2.86
3-3.2
Transparency
Transparent to Translucent
Opaque
Density
2.7-2.9 g/cm3
2.8-2.9 g/cm3
Resistance
Heat Resistant
Impact Resistant, Pressure Resistant
Deposits in Eastern Continents
Asia
South Korea
Japan, Turkey
Africa
Western Africa
Egypt, Ethiopia, South Africa
Europe
Great Britain, Switzerland
France, Greece, Iceland
Deposits in Western Continents
Deposits in Oceania Continent
Australia
Central Australia, Western Australia
New Zealand
Pseudotachylite vs Blueschist 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. Pseudotachylite vs Blueschist characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Pseudotachylite and Properties of Blueschist. Learn more about Pseudotachylite vs Blueschist in the next section. The interior uses of Pseudotachylite include Decorative aggregates, Entryways and Interior decoration whereas the interior uses of Blueschist include Floor tiles, Flooring, Homes, Hotels and Kitchens. Due to some exceptional properties of Pseudotachylite and Blueschist, they have various applications in construction industry. The uses of Pseudotachylite in construction industry include As dimension stone, Cement manufacture, For road aggregate, Making natural cement and that of Blueschist include As dimension stone, Cobblestones, Rail track ballast, Roadstone.
More about Pseudotachylite and Blueschist
Here you can know more about Pseudotachylite and Blueschist. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Pseudotachylite and Blueschist consists of mineral content and compound content. The mineral content of Pseudotachylite includes Iron Oxides, Pyroxene, Quartz, Stishovite, Sulfides and mineral content of Blueschist includes Albite, Chlorite, Epidote, Garnet, Glaucophane, Lawsonite, Muscovite or Illite, Quartz. You can also check out the list of all Metamorphic Rocks. When we have to compare Pseudotachylite vs Blueschist, the texture, color and appearance plays an important role in determining the type of rock. Pseudotachylite is available in black, brown, green, grey, pink, white colors whereas, Blueschist is available in blue, bluish - grey, purple, shades of blue colors. Appearance of Pseudotachylite is Dull and Soft and that of Blueschist is Dull and Banded. Properties of rock is another aspect for Pseudotachylite vs Blueschist. The hardness of Pseudotachylite is 7 and that of Blueschist is 3.5-4. The types of Pseudotachylite are Cataclastic rock whereas types of Blueschist are Metamorphic rock. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Pseudotachylite is light to dark brown while that of Blueschist is white to grey. The specific heat capacity of Pseudotachylite is 0.92 kJ/Kg K and that of Blueschist 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.Pseudotachylite is heat resistant whereas Blueschist is impact resistant, pressure resistant.