Definition
Very fine grained fault rock which is composed of glassy matrix that often contains inclusions of wall-rock fragments.
Felsite is a very fine grained volcanic rock that may or may not contain larger crystals and light colored rock that typically requires petrographic examination or chemical analysis for more precise definition
Discoverer
Unknown
Unknown
Etymology
From pseudo- + tachylite, a glassy rock generated by frictional heat within faults.
From English feldspar and -ite
Class
Metamorphic Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Quench
Arborescent Patterned, Vitreous
Color
Black, Brown, Green, Grey, Pink, White
Black, Blue, Brown, Green, Orange, Red, Tan, Yellow
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Dull and Soft
Layered, Banded, Veined and Shiny
Interior Uses
Decorative Aggregates, Entryways, Interior Decoration
Decorative Aggregates, Flooring, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration
Paving Stone, Garden Decoration
Other Architectural Uses
Curbing
Curbing
Construction Industry
As Dimension Stone, Cement Manufacture, for Road Aggregate, Making natural cement
Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points
Medical Industry
-
Surgery
Antiquity Uses
Artifacts, Monuments
Artifacts
Commercial Uses
Creating Artwork, Gemstone
Mirror, Jewelry
Types
Cataclastic rock
Igneous rock
Features
Host Rock for Lead
Available in Lots of Colors and Patterns, Clasts are smooth to touch, Splintery, 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.
Felsite is a fine-grained, hard rock which is a type of metasomatite, essentially altered basalt. It forms with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.
Mineral Content
Iron Oxides, Pyroxene, Quartz, Stishovite, Sulfides
Feldspar, Iron Oxides
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, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism
Types of Weathering
-
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
-
Chemical Erosion, Glacier Erosion, Water Erosion
Grain Size
Very fine-grained
Fine Grained
Fracture
Uneven
Conchoidal
Streak
Light to dark brown
White
Porosity
Less Porous
Very Less Porous
Specific Gravity
2.46-2.86
2.6-2.7
Transparency
Transparent to Translucent
Translucent
Density
2.7-2.9 g/cm3
2.6 g/cm3
Resistance
Heat Resistant
Heat Resistant, Impact Resistant
Deposits in Eastern Continents
Asia
South Korea
Afghanistan, Indonesia, Japan, Russia
Africa
Western Africa
Kenya
Europe
Great Britain, Switzerland
Greece, Hungary, Iceland, Italy, Turkey
Deposits in Western Continents
North America
-
Canada, Mexico, USA
South America
-
Argentina, Chile, Ecuador, Peru
Deposits in Oceania Continent
Australia
Central Australia, Western Australia
New Zealand
Pseudotachylite vs Felsite 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 Felsite characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Pseudotachylite and Properties of Felsite. Learn more about Pseudotachylite vs Felsite in the next section. The interior uses of Pseudotachylite include Decorative aggregates, Entryways and Interior decoration whereas the interior uses of Felsite include Decorative aggregates, Flooring and Interior decoration. Due to some exceptional properties of Pseudotachylite and Felsite, 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 Felsite include Arrowheads, Cutting tool, Knives, Scrapers, Spear points.
More about Pseudotachylite and Felsite
Here you can know more about Pseudotachylite and Felsite. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Pseudotachylite and Felsite consists of mineral content and compound content. The mineral content of Pseudotachylite includes Iron Oxides, Pyroxene, Quartz, Stishovite, Sulfides and mineral content of Felsite includes Feldspar, Iron Oxides. You can also check out the list of all Metamorphic Rocks. When we have to compare Pseudotachylite vs Felsite, 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, Felsite is available in black, blue, brown, green, orange, red, tan, yellow colors. Appearance of Pseudotachylite is Dull and Soft and that of Felsite is Layered, Banded, Veined and Shiny. Properties of rock is another aspect for Pseudotachylite vs Felsite. The hardness of Pseudotachylite is 7 and that of Felsite is 5-5.5. The types of Pseudotachylite are Cataclastic rock whereas types of Felsite are Igneous 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 Felsite is white. The specific heat capacity of Pseudotachylite is 0.92 kJ/Kg K and that of Felsite is 0.92 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 Felsite is heat resistant, impact resistant.