Definition
Blueschist is a metamorphic rock which is generally blue in color and is formed under conditions of high pressure and low temperature
Tephrite is an aphanitic to porphyritic textured, volcanic igneous rock
Discoverer
Edgar Bailey
Van Tooren
Etymology
From French schiste, Greek skhistos i.e. split
From Greek tephra, ashes from Indo-European base, to burn
Class
Metamorphic Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Other Categories
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Foliated
Aphanitic to Porphyritic
Color
Blue, Bluish - Grey, Purple, Shades of Blue
Black, Brown, Green, Grey, White
Durability
Durable
Durable
Appearance
Dull and Banded
Vesicular
Interior Uses
Floor Tiles, Flooring, Homes, Hotels, Kitchens
Decorative Aggregates, Flooring, Homes, Interior Decoration
Exterior Uses
Garden Decoration, Office Buildings
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings
Other Architectural Uses
-
Curbing
Construction Industry
As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone
Landscaping
Antiquity Uses
Artifacts, Monuments, Sculpture
Artifacts, Sculpture
Commercial Uses
Cemetery Markers, Commemorative Tablets, Creating Artwork, Curling, Tombstones
Production of Lime, Soil Conditioner
Types
Metamorphic rock
Igneous rock
Features
Has High structural resistance against erosion and climate, Very fine grained rock
Host Rock for Lead
Archaeological Significance
Formation
Blueschist forms due to the metamorphism of basalt and other rocks with similar composition at high pressures and low temperatures and approximately corresponding to a depth of 15 to 30 kilometers and 200 to 500 °C.
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.
Mineral Content
Albite, Chlorite, Epidote, Garnet, Glaucophane, Lawsonite, Muscovite or Illite, Quartz
Alkali feldspar, Nepheline, Plagioclase, Pyroxene
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
CaO, Carbon Dioxide, MgO, Silicon Dioxide
Types of Metamorphism
-
Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism
Types of Weathering
Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Water Erosion, Wind Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion
Grain Size
Fine to Medium Grained
Medium to Fine Coarse Grained
Fracture
Conchoidal
Uneven
Streak
White to Grey
Bluish Black
Porosity
Highly Porous
Very Less Porous
Luster
Dull
Subvitreous to Dull
Cleavage
Slaty
Crenulation and Pervasive
Specific Gravity
3-3.2
2.86
Transparency
Opaque
Opaque
Density
2.8-2.9 g/cm3
2.8-2.9 g/cm3
Resistance
Impact Resistant, Pressure Resistant
Heat Resistant, Impact Resistant
Deposits in Eastern Continents
Africa
Egypt, Ethiopia, South Africa
Namibia, Uganda
Europe
France, Greece, Iceland
Germany, Hungary, Italy, Portugal, Spain
Deposits in Western Continents
Deposits in Oceania Continent
Australia
New Zealand
New Zealand, Western Australia
Blueschist vs Tephrite 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. Blueschist vs Tephrite characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Blueschist and Properties of Tephrite. Learn more about Blueschist vs Tephrite in the next section. The interior uses of Blueschist include Floor tiles, Flooring, Homes, Hotels and Kitchens whereas the interior uses of Tephrite include Decorative aggregates, Flooring, Homes and Interior decoration. Due to some exceptional properties of Blueschist and Tephrite, they have various applications in construction industry. The uses of Blueschist in construction industry include As dimension stone, Cobblestones, Rail track ballast, Roadstone and that of Tephrite include Landscaping.
More about Blueschist and Tephrite
Here you can know more about Blueschist and Tephrite. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Blueschist and Tephrite consists of mineral content and compound content. The mineral content of Blueschist includes Albite, Chlorite, Epidote, Garnet, Glaucophane, Lawsonite, Muscovite or Illite, Quartz and mineral content of Tephrite includes Alkali feldspar, Nepheline, Plagioclase, Pyroxene. You can also check out the list of all Igneous Rocks. When we have to compare Blueschist vs Tephrite, the texture, color and appearance plays an important role in determining the type of rock. Blueschist is available in blue, bluish - grey, purple, shades of blue colors whereas, Tephrite is available in black, brown, green, grey, white colors. Appearance of Blueschist is Dull and Banded and that of Tephrite is Vesicular. Properties of rock is another aspect for Blueschist vs Tephrite. The hardness of Blueschist is 3.5-4 and that of Tephrite is 6.5. The types of Blueschist are Metamorphic rock whereas types of Tephrite are Igneous rock. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Blueschist is white to grey while that of Tephrite is bluish black. The specific heat capacity of Blueschist is 0.84 kJ/Kg K and that of Tephrite 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.Blueschist is impact resistant, pressure resistant whereas Tephrite is heat resistant, impact resistant.