Definition
Tephrite is an aphanitic to porphyritic textured, volcanic igneous rock
Websterite is ultramafic and ultrabasic rock that consists of roughly equal proportions of orthopyroxene and clinopyroxene. It is a special type of pyroxenite.
Origin
Germany
Webster, North Carolina
Discoverer
Van Tooren
Unknown
Etymology
From Greek tephra, ashes from Indo-European base, to burn
From the town of Webster located in North Carolina
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
Other Categories
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock
Texture
Aphanitic to Porphyritic
Clastic, Granular, Phaneritic, Porphyritic
Color
Black, Brown, Green, Grey, White
Black to Grey, Bluish - Grey, Dark Greenish - Grey, Green, Light Greenish Grey
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Vesicular
Layered, Banded, Veined and Shiny
Interior Uses
Decorative Aggregates, Flooring, Homes, Interior Decoration
Countertops, Decorative Aggregates, Entryways, Floor Tiles, Flooring, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
Other Architectural Uses
Curbing
Curbing
Construction Industry
Landscaping
As Dimension Stone, Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate
Antiquity Uses
Artifacts, Sculpture
Artifacts
Commercial Uses
Production of Lime, Soil Conditioner
Cemetery Markers, Commemorative Tablets, Creating Artwork, Laboratory bench tops, Jewelry, Sea Defence, Tombstones
Types
Igneous rock
Ultramafic rock
Features
Host Rock for Lead
Generally rough to touch, Is one of the oldest rock
Archaeological Significance
Formation
Tephrite 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.
Websterite can be formed as cumulates in ultramafic intrusions by accumulation of pyroxene crystals at the base of the lava chamber.
Mineral Content
Alkali feldspar, Nepheline, Plagioclase, Pyroxene
Amphibole, Augite, Bronzite, Chromite, Diopside, Enstatite, Garnet, Hornblende, Hypersthene, Magnetite, Pyroxene
Compound Content
CaO, Carbon Dioxide, MgO, Silicon Dioxide
Aluminium Oxide, CaO, Chromium(III) Oxide, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Sulfur Trioxide
Types of Metamorphism
Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism
Burial Metamorphism, Impact Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Water Erosion, Wind Erosion
Grain Size
Medium to Fine Coarse Grained
Coarse Grained
Streak
Bluish Black
White, Greenish White or Grey
Porosity
Very Less Porous
Less Porous
Luster
Subvitreous to Dull
Dull to Vitreous to Submetallic
Cleavage
Crenulation and Pervasive
-
Specific Gravity
2.86
3.2-3.5
Transparency
Opaque
Opaque
Density
2.8-2.9 g/cm3
3.1-3.6 g/cm3
Resistance
Heat Resistant, Impact Resistant
Impact Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Africa
Namibia, Uganda
South Africa
Europe
Germany, Hungary, Italy, Portugal, Spain
Germany, Greece, Italy, Scotland, Turkey
Deposits in Western Continents
North America
USA
Canada, USA
South America
-
Brazil, Colombia, Venezuela
Deposits in Oceania Continent
Australia
New Zealand, Western Australia
New Zealand, Queensland
Tephrite vs Websterite 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. Tephrite vs Websterite characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Tephrite and Properties of Websterite. Learn more about Tephrite vs Websterite in the next section. The interior uses of Tephrite include Decorative aggregates, Flooring, Homes and Interior decoration whereas the interior uses of Websterite include Countertops, Decorative aggregates, Entryways, Floor tiles, Flooring and Interior decoration. Due to some exceptional properties of Tephrite and Websterite, they have various applications in construction industry. The uses of Tephrite in construction industry include Landscaping and that of Websterite include As dimension stone, Building houses or walls, Cement manufacture, Construction aggregate, For road aggregate.
More about Tephrite and Websterite
Here you can know more about Tephrite and Websterite. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Tephrite and Websterite consists of mineral content and compound content. The mineral content of Tephrite includes Alkali feldspar, Nepheline, Plagioclase, Pyroxene and mineral content of Websterite includes Amphibole, Augite, Bronzite, Chromite, Diopside, Enstatite, Garnet, Hornblende, Hypersthene, Magnetite, Pyroxene. You can also check out the list of all Igneous Rocks. When we have to compare Tephrite vs Websterite, the texture, color and appearance plays an important role in determining the type of rock. Tephrite is available in black, brown, green, grey, white colors whereas, Websterite is available in black to grey, bluish - grey, dark greenish - grey, green, light greenish grey colors. Appearance of Tephrite is Vesicular and that of Websterite is Layered, Banded, Veined and Shiny. Properties of rock is another aspect for Tephrite vs Websterite. The hardness of Tephrite is 6.5 and that of Websterite is 7. The types of Tephrite are Igneous rock whereas types of Websterite are Ultramafic rock. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Tephrite is bluish black while that of Websterite is white, greenish white or grey. The specific heat capacity of Tephrite is 0.92 kJ/Kg K and that of Websterite 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.Tephrite is heat resistant, impact resistant whereas Websterite is impact resistant, pressure resistant, wear resistant.