Definition
Very fine grained fault rock which is composed of glassy matrix that often contains inclusions of wall-rock fragments.
Rapakivi Granite is a hornblende-biotite Granite containing large rounded crystals of orthoclase which are mantled with oligoclase
Origin
USA
Finland, Europe
Discoverer
Unknown
Jakob Sederholm
Etymology
From pseudo- + tachylite, a glassy rock generated by frictional heat within faults.
From Finnish Rapakivi which stands for crumbly rock
Class
Metamorphic Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock
Texture
Quench
Granular, Phaneritic
Color
Black, Brown, Green, Grey, Pink, White
Black, Grey, Orange, Pink, White
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Dull and Soft
Veined or Pebbled
Interior Uses
Decorative Aggregates, Entryways, Interior Decoration
Bathrooms, Countertops, Decorative Aggregates, Entryways, Floor Tiles, Flooring, Homes, Hotels, Interior Decoration, Kitchens, Stair Treads
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration
As Building Stone, As Facing Stone, Office Buildings, Paving Stone, Resorts
Other Architectural Uses
Curbing
-
Construction Industry
As Dimension Stone, Cement Manufacture, for Road Aggregate, Making natural cement
As Dimension Stone
Antiquity Uses
Artifacts, Monuments
Artifacts, Monuments, Sculpture, Small Figurines
Commercial Uses
Creating Artwork, Gemstone
Cemetery Markers, Commemorative Tablets, Creating Artwork, Curling, Laboratory bench tops, Tombstones
Types
Cataclastic rock
Igneous Protolith Granite, Sedimentary Protolith Granite, Mantle Granite, Anorogenic Granite and Hybrid Granite
Features
Host Rock for Lead
Available in Lots of Colors and Patterns, It is One of the Oldest, Strongest and Hardest 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.
Granite is an igneous rock which is very hard, crystalline and is visibly homogeneous in texture and forms by melting of continental rocks
Mineral Content
Iron Oxides, Pyroxene, Quartz, Stishovite, Sulfides
Amphibole, Biotite, Feldspar, Hornblade, Micas, Muscovite or Illite, Plagioclase, Pyroxene, 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
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
Types of Weathering
-
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
-
Chemical Erosion, Coastal Erosion, Water Erosion, Wind Erosion
Grain Size
Very fine-grained
Large and Coarse Grained
Streak
Light to dark brown
White
Porosity
Less Porous
Less Porous
Luster
Vitreous
Dull to Grainy with Sporadic parts Pearly and Vitreous
Specific Gravity
2.46-2.86
2.6-2.7
Transparency
Transparent to Translucent
Opaque
Density
2.7-2.9 g/cm3
2.6-2.8 g/cm3
Resistance
Heat Resistant
Heat Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
South Korea
China, India, Iran, Saudi Arabia, Sri Lanka, Taiwan, Thailand, Turkey, Vietnam
Africa
Western Africa
Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa
Europe
Great Britain, Switzerland
Austria, Belgium, Finland, France, Germany, Italy, Norway, Sardinia, Spain, Switzerland, The Czech Republic
Deposits in Western Continents
North America
-
Canada, USA
Deposits in Oceania Continent
Australia
Central Australia, Western Australia
-
Pseudotachylite vs Rapakivi Granite 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 Rapakivi Granite characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Pseudotachylite and Properties of Rapakivi Granite. Learn more about Pseudotachylite vs Rapakivi Granite in the next section. The interior uses of Pseudotachylite include Decorative aggregates, Entryways and Interior decoration whereas the interior uses of Rapakivi Granite include Bathrooms, Countertops, Decorative aggregates, Entryways, Floor tiles, Flooring, Homes, Hotels, Interior decoration, Kitchens and Stair treads. Due to some exceptional properties of Pseudotachylite and Rapakivi Granite, 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 Rapakivi Granite include As dimension stone.
More about Pseudotachylite and Rapakivi Granite
Here you can know more about Pseudotachylite and Rapakivi Granite. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Pseudotachylite and Rapakivi Granite consists of mineral content and compound content. The mineral content of Pseudotachylite includes Iron Oxides, Pyroxene, Quartz, Stishovite, Sulfides and mineral content of Rapakivi Granite includes Amphibole, Biotite, Feldspar, Hornblade, Micas, Muscovite or Illite, Plagioclase, Pyroxene, Quartz. You can also check out the list of all Metamorphic Rocks. When we have to compare Pseudotachylite vs Rapakivi Granite, 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, Rapakivi Granite is available in black, grey, orange, pink, white colors. Appearance of Pseudotachylite is Dull and Soft and that of Rapakivi Granite is Veined or Pebbled. Properties of rock is another aspect for Pseudotachylite vs Rapakivi Granite. The hardness of Pseudotachylite is 7 and that of Rapakivi Granite is 6-7. The types of Pseudotachylite are Cataclastic rock whereas types of Rapakivi Granite are Igneous Protolith Granite, Sedimentary Protolith Granite, Mantle Granite, Anorogenic Granite and Hybrid Granite. 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 Rapakivi Granite is white. The specific heat capacity of Pseudotachylite is 0.92 kJ/Kg K and that of Rapakivi Granite is 0.79 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 Rapakivi Granite is heat resistant, wear resistant.