Definition
Very fine grained fault rock which is composed of glassy matrix that often contains inclusions of wall-rock fragments.
Gritstone or grit is a hard, coarse-grained, siliceous sandstone
Origin
USA
Pennines, England
Discoverer
Unknown
J.J. Ferber
Etymology
From pseudo- + tachylite, a glassy rock generated by frictional heat within faults.
From Grit + Stone
Class
Metamorphic Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock
Color
Black, Brown, Green, Grey, Pink, White
Beige, Black, Brown, Cream, Dark Brown, Green, Grey, Light Green, Light to Dark Grey, Pink, Red, White, Yellow
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Dull and Soft
Layered and Foliated
Interior Uses
Decorative Aggregates, Entryways, Interior Decoration
Countertops, Decorative Aggregates, Homes, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration
As Building Stone, Garden Decoration, Office Buildings, Paving Stone
Other Architectural Uses
Curbing
Curbing
Construction Industry
As Dimension Stone, Cement Manufacture, for Road Aggregate, Making natural cement
Construction Aggregate, Roadstone
Antiquity Uses
Artifacts, Monuments
Artifacts, Monuments, Sculpture
Commercial Uses
Creating Artwork, Gemstone
An Oil and Gas Reservoir, As a Feed Additive for Livestock, Gemstone, Metallurgical Flux, Production of Lime, Soil Conditioner, Source of Magnesia (MgO), Tombstones
Types
Cataclastic rock
Sedimentary rock
Features
Host Rock for Lead
Available in Lots of Colors and Patterns, Generally rough to touch, 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.
Gritstone is a type of sedimentary rock which was formed on the floors of wide river deltas where the grit deposits were laid down, with every tide or flood dumping another layer of sediment.
Mineral Content
Iron Oxides, Pyroxene, Quartz, Stishovite, Sulfides
Calcite, Clay Minerals, Feldspar, Micas, Quartz
Compound Content
Carbon Dioxide, Silicon Dioxide, Sulfur Dioxide, Sulphur
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
-
Types of Weathering
-
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
-
Chemical Erosion, Coastal Erosion
Grain Size
Very fine-grained
Coarse Grained
Fracture
Uneven
Conchoidal
Streak
Light to dark brown
White
Porosity
Less Porous
Highly Porous
Specific Gravity
2.46-2.86
2.250
Transparency
Transparent to Translucent
Opaque
Density
2.7-2.9 g/cm3
2.2 g/cm3
Resistance
Heat Resistant
Heat Resistant, Impact Resistant, Pressure Resistant
Deposits in Eastern Continents
Asia
South Korea
China, India, Kazakhstan, Mongolia, Russia, Uzbekistan
Africa
Western Africa
Namibia, Nigeria, South Africa
Europe
Great Britain, Switzerland
Austria, Denmark, Germany, Great Britain, Netherlands, Poland, Sweden, Switzerland, United Kingdom
Deposits in Western Continents
North America
-
Canada, USA
Deposits in Oceania Continent
Australia
Central Australia, Western Australia
New South Wales, New Zealand, Western Australia
All about Pseudotachylite and Gritstone Properties
Know all about Pseudotachylite and Gritstone properties here. All properties of rocks are important as they define the type of rock and its application. Pseudotachylite belongs to Metamorphic Rocks while Gritstone belongs to Sedimentary Rocks.Texture of Pseudotachylite is Quench whereas that of Gritstone is Earthy. Pseudotachylite appears Dull and Soft and Gritstone appears Layered and Foliated. The luster of Pseudotachylite is vitreous while that of Gritstone is dull. Pseudotachylite is available in black, brown, green, grey, pink, white colors whereas Gritstone is available in beige, black, brown, cream, dark brown, green, grey, light green, light to dark grey, pink, red, white, yellow colors. The commercial uses of Pseudotachylite are creating artwork, gemstone and that of Gritstone are an oil and gas reservoir, as a feed additive for livestock, gemstone, metallurgical flux, production of lime, soil conditioner, source of magnesia (mgo), tombstones.