Definition
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
Very fine grained fault rock which is composed of glassy matrix that often contains inclusions of wall-rock fragments.
Discoverer
Unknown
Unknown
Etymology
From English feldspar and -ite
From pseudo- + tachylite, a glassy rock generated by frictional heat within faults.
Class
Igneous Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Group
Volcanic
Not Applicable
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Arborescent Patterned, Vitreous
Quench
Color
Black, Blue, Brown, Green, Orange, Red, Tan, Yellow
Black, Brown, Colourless, Green, Grey, Pink, White
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Layered, Banded, Veined and Shiny
Dull and Soft
Interior Uses
Decorative Aggregates, Flooring, Interior Decoration
Decorative Aggregates, Entryways, Interior Decoration
Exterior Uses
Paving Stone, Garden Decoration
As Building Stone, As Facing Stone, Garden Decoration
Other Architectural Uses
Curbing
Curbing
Construction Industry
Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points
As Dimension Stone, Cement Manufacture, for Road Aggregate, Making natural cement
Medical Industry
Surgery
Not Yet Used
Antiquity Uses
Artifacts
Artifacts, Monuments
Commercial Uses
Mirror, Jewelry
Creating Artwork, Gemstone
Types
Not Available
Not Available
Features
Available in Lots of Colors and Patterns, Clasts are smooth to touch, Splintery, Very fine grained rock
Host Rock for Lead
Archaeological Significance
Monuments
Not Yet Used
Used
Famous Monuments
Not Applicable
Data Not Available
Sculpture
Not Yet Used
Not Yet Used
Famous Sculptures
Not Applicable
Not Applicable
Pictographs
Used
Not Used
Petroglyphs
Used
Not Used
Figurines
Not Yet Used
Not Yet Used
Formation
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.
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.
Mineral Content
Feldspar, Iron Oxides
Iron Oxides, Pyroxene, Quartz, Stishovite, Sulfides
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Carbon Dioxide, Silicon Dioxide, Sulfur Dioxide, Sulphur
Types of Metamorphism
Burial Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Not Applicable
Types of Erosion
Chemical Erosion, Glacier Erosion, Water Erosion
Not Applicable
Grain Size
Fine Grained
Very fine-grained
Fracture
Conchoidal
Uneven
Streak
White
Light to dark brown
Porosity
Very Less Porous
Less Porous
Cleavage
Non-Existent
Irregular
Toughness
Not Available
Not Available
Specific Gravity
2.6-2.7
2.46-2.86
Transparency
Translucent
Transparent to Translucent
Density
2.6 g/cm3
2.7-2.9 g/cm3
Resistance
Heat Resistant, Impact Resistant
Heat Resistant
Deposits in Eastern Continents
Asia
Afghanistan, Indonesia, Japan, Russia
South Korea
Africa
Kenya
Western Africa
Europe
Greece, Hungary, Iceland, Italy, Turkey
Great Britain, Switzerland
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
Canada, Mexico, USA
Not Yet Found
South America
Argentina, Chile, Ecuador, Peru
Not Yet Found
Deposits in Oceania Continent
Australia
New Zealand
Central Australia, Western Australia
All about Felsite and Pseudotachylite Properties
Know all about Felsite and Pseudotachylite properties here. All properties of rocks are important as they define the type of rock and its application. Felsite belongs to Igneous Rocks while Pseudotachylite belongs to Metamorphic Rocks.Texture of Felsite is Arborescent Patterned, Vitreous whereas that of Pseudotachylite is Quench. Felsite appears Layered, Banded, Veined and Shiny and Pseudotachylite appears Dull and Soft. The luster of Felsite and Pseudotachylite is vitreous. Felsite is available in black, blue, brown, green, orange, red, tan, yellow colors whereas Pseudotachylite is available in black, brown, colourless, green, grey, pink, white colors. The commercial uses of Felsite are mirror, jewelry and that of Pseudotachylite are creating artwork, gemstone.