Definition
Picrite is a variety of high-magnesium olivine basalt that is very rich in the mineral olivine
Tephrite is an aphanitic to porphyritic textured, volcanic igneous rock
Origin
Hawaii Islands
Germany
Discoverer
Unknown
Van Tooren
Etymology
From Greek pikros bitter + -ite, 19th century
From Greek tephra, ashes from Indo-European base, to burn
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Earthy, Rough
Aphanitic to Porphyritic
Color
Black, Brown, Green, Grey, Pink, White, Yellow
Black, Brown, Green, Grey, White
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Rough and Shiny
Vesicular
Interior Uses
Countertops, Decorative Aggregates, Homes, Interior Decoration
Decorative Aggregates, Flooring, Homes, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings
Other Architectural Uses
Curbing
Curbing
Construction Industry
As a Sintering Agent in Steel Industry to process Iron Ore, Cement Manufacture, for Road Aggregate, Manufacture of Magnesium and Dolomite Refractories, Roadstone, Used for flooring, stair treads, borders and window sills.
Landscaping
Antiquity Uses
Artifacts, Monuments, Sculpture
Artifacts, Sculpture
Commercial Uses
As a Feed Additive for Livestock, As armour rock for sea walls, Metallurgical Flux, Pottery, Source of Magnesia (MgO)
Production of Lime, Soil Conditioner
Types
Oceanite
Igneous rock
Features
Host Rock for Lead
Host Rock for Lead
Archaeological Significance
Formation
Picrite 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.
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
Biotite, Olivine, Plagioclase, Pyrrhotite
Alkali feldspar, Nepheline, Plagioclase, Pyroxene
Compound Content
Al, CaO, Carbon Dioxide, Mg, MgO
CaO, Carbon Dioxide, MgO, Silicon Dioxide
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Impact Metamorphism, Regional Metamorphism
Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism
Types of Weathering
Biological Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion
Grain Size
Fine Grained
Medium to Fine Coarse Grained
Streak
White, Greenish White or Grey
Bluish Black
Porosity
Less Porous
Very Less Porous
Luster
Subvitreous to Dull
Subvitreous to Dull
Cleavage
-
Crenulation and Pervasive
Specific Gravity
2.75-2.92
2.86
Transparency
Opaque
Opaque
Density
1.5-2.5 g/cm3
2.8-2.9 g/cm3
Resistance
Heat Resistant
Heat Resistant, Impact Resistant
Deposits in Eastern Continents
Africa
South Africa
Namibia, Uganda
Europe
Iceland
Germany, Hungary, Italy, Portugal, Spain
Deposits in Western Continents
North America
Canada, USA
USA
Deposits in Oceania Continent
Australia
-
New Zealand, Western Australia
All about Picrite and Tephrite Properties
Know all about Picrite and Tephrite properties here. All properties of rocks are important as they define the type of rock and its application. Picrite and Tephrite belong to Igneous Rocks.Texture of Picrite is Earthy, Rough whereas that of Tephrite is Aphanitic to Porphyritic. Picrite appears Rough and Shiny and Tephrite appears Vesicular. The luster of Picrite and Tephrite is subvitreous to dull. Picrite and Tephrite are available in black, brown, green, grey, pink, white, yellow colors. The commercial uses of Picrite are as a feed additive for livestock, as armour rock for sea walls, metallurgical flux, pottery, source of magnesia (mgo) and that of Tephrite are production of lime, soil conditioner.