Tephrite

Picrite

Tephrite and Picrite

Tephrite

Picrite

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Definition

Tephrite is an aphanitic to porphyritic textured, volcanic igneous rock

Picrite is a variety of high-magnesium olivine basalt that is very rich in the mineral olivine

History

Origin

Germany

Hawaii Islands

Discoverer

Van Tooren

Unknown

Etymology

From Greek tephra, ashes from Indo-European base, to burn

From Greek pikros bitter + -ite, 19th century

Class

Igneous Rocks

Sub-Class

Durable Rock, Hard Rock

Family

Group

Volcanic

Other Categories

Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock

Fine Grained Rock, Opaque Rock

Texture

Aphanitic to Porphyritic

Earthy, Rough

Color

Black, Brown, Green, Grey, White

Black, Brown, Green, Grey, Pink, White, Yellow

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Vesicular

Rough and Shiny

Uses

Architecture

Interior Uses

Decorative Aggregates, Flooring, Homes, Interior Decoration

Countertops, Decorative Aggregates, Homes, 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

Industry

Construction Industry

Landscaping

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.

Medical Industry

Antiquity Uses

Artifacts, Sculpture

Artifacts, Monuments, Sculpture

Other Uses

Commercial Uses

Production of Lime, Soil Conditioner

As a Feed Additive for Livestock, As armour rock for sea walls, Metallurgical Flux, Pottery, Source of Magnesia (MgO)

Types

Igneous rock

Oceanite

Features

Host Rock for Lead

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

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.

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.

Composition

Mineral Content

Alkali feldspar, Nepheline, Plagioclase, Pyroxene

Biotite, Olivine, Plagioclase, Pyrrhotite

Compound Content

CaO, Carbon Dioxide, MgO, Silicon Dioxide

Al, CaO, Carbon Dioxide, Mg, MgO

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Impact Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Biological Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion

Properties

Physical Properties

Hardness

6.56.8

1 7

👆🏻

Grain Size

Medium to Fine Coarse Grained

Fine Grained

Fracture

Uneven

Streak

Bluish Black

White, Greenish White or Grey

Porosity

Very Less Porous

Less Porous

Luster

Subvitreous to Dull

Compressive Strength

90.00 N/mm²189.00 N/mm²

0.15 450

👆🏻

Cleavage

Crenulation and Pervasive

Toughness

2.4

2.1

Specific Gravity

2.862.75-2.92

0 8.4

👆🏻

Transparency

Opaque

Density

2.8-2.9 g/cm³1.5-2.5 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.92 kJ/Kg K0.88 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant

Heat Resistant

Reserves

Deposits in Eastern Continents

Asia

India, Russia

Africa

Namibia, Uganda

South Africa

Europe

Germany, Hungary, Italy, Portugal, Spain

Iceland

Others

Deposits in Western Continents

North America

USA

Canada, USA

South America

Brazil

Deposits in Oceania Continent

Australia

New Zealand, Western Australia

All about Tephrite and Picrite Properties

Know all about Tephrite and Picrite properties here. All properties of rocks are important as they define the type of rock and its application. Tephrite and Picrite belong to Igneous Rocks.Texture of Tephrite is Aphanitic to Porphyritic whereas that of Picrite is Earthy, Rough. Tephrite appears Vesicular and Picrite appears Rough and Shiny. The luster of Tephrite and Picrite is subvitreous to dull. Tephrite is available in black, brown, green, grey, white colors whereas Picrite is available in black, brown, green, grey, pink, white, yellow colors. The commercial uses of Tephrite are production of lime, soil conditioner and that of Picrite are as a feed additive for livestock, as armour rock for sea walls, metallurgical flux, pottery, source of magnesia (mgo).