Definition
Very fine grained fault rock which is composed of glassy matrix that often contains inclusions of wall-rock fragments.
Websterite is ultramafic and ultrabasic rock that consists of roughly equal proportions of orthopyroxene and clinopyroxene. It is a special type of pyroxenite.
Origin
USA
Webster, North Carolina
Discoverer
Unknown
Unknown
Etymology
From pseudo- + tachylite, a glassy rock generated by frictional heat within faults.
From the town of Webster located in North Carolina
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
Clastic, Granular, Phaneritic, Porphyritic
Color
Black, Brown, Green, Grey, Pink, White
Black to Grey, Bluish - Grey, Dark Greenish - Grey, Green, Light Greenish Grey
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Dull and Soft
Layered, Banded, Veined and Shiny
Interior Uses
Decorative Aggregates, Entryways, Interior Decoration
Countertops, Decorative Aggregates, Entryways, Floor Tiles, Flooring, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
Other Architectural Uses
Curbing
Curbing
Construction Industry
As Dimension Stone, Cement Manufacture, for Road Aggregate, Making natural cement
As Dimension Stone, Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate
Antiquity Uses
Artifacts, Monuments
Artifacts
Commercial Uses
Creating Artwork, Gemstone
Cemetery Markers, Commemorative Tablets, Creating Artwork, Laboratory bench tops, Jewelry, Sea Defence, Tombstones
Types
Cataclastic rock
Ultramafic rock
Features
Host Rock for Lead
Generally rough to touch, Is one of the oldest 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.
Websterite can be formed as cumulates in ultramafic intrusions by accumulation of pyroxene crystals at the base of the lava chamber.
Mineral Content
Iron Oxides, Pyroxene, Quartz, Stishovite, Sulfides
Amphibole, Augite, Bronzite, Chromite, Diopside, Enstatite, Garnet, Hornblende, Hypersthene, Magnetite, Pyroxene
Compound Content
Carbon Dioxide, Silicon Dioxide, Sulfur Dioxide, Sulphur
Aluminium Oxide, CaO, Chromium(III) Oxide, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Sulfur Trioxide
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
Burial Metamorphism, Impact Metamorphism
Types of Weathering
-
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
-
Chemical Erosion, Coastal Erosion, Glacier Erosion, Water Erosion, Wind Erosion
Grain Size
Very fine-grained
Coarse Grained
Streak
Light to dark brown
White, Greenish White or Grey
Porosity
Less Porous
Less Porous
Luster
Vitreous
Dull to Vitreous to Submetallic
Specific Gravity
2.46-2.86
3.2-3.5
Transparency
Transparent to Translucent
Opaque
Density
2.7-2.9 g/cm3
3.1-3.6 g/cm3
Resistance
Heat Resistant
Impact Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
South Korea
India, Russia
Africa
Western Africa
South Africa
Europe
Great Britain, Switzerland
Germany, Greece, Italy, Scotland, Turkey
Deposits in Western Continents
North America
-
Canada, USA
South America
-
Brazil, Colombia, Venezuela
Deposits in Oceania Continent
Australia
Central Australia, Western Australia
New Zealand, Queensland
All about Pseudotachylite and Websterite Properties
Know all about Pseudotachylite and Websterite properties here. All properties of rocks are important as they define the type of rock and its application. Pseudotachylite belongs to Metamorphic Rocks while Websterite belongs to Igneous Rocks.Texture of Pseudotachylite is Quench whereas that of Websterite is Clastic, Granular, Phaneritic, Porphyritic. Pseudotachylite appears Dull and Soft and Websterite appears Layered, Banded, Veined and Shiny. The luster of Pseudotachylite is vitreous while that of Websterite is dull to vitreous to submetallic. Pseudotachylite is available in black, brown, green, grey, pink, white colors whereas Websterite is available in black to grey, bluish - grey, dark greenish - grey, green, light greenish grey colors. The commercial uses of Pseudotachylite are creating artwork, gemstone and that of Websterite are cemetery markers, commemorative tablets, creating artwork, laboratory bench tops, jewelry, sea defence, tombstones.