Tephrite

Hornfels

Tephrite and Hornfels

Tephrite

Hornfels

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Definition

Tephrite is an aphanitic to porphyritic textured, volcanic igneous rock

Hornfels is a metamorphic rock formed by the contact between mudstone or other clay rich rock, and a hot igneous body, and represents a heat altered equivalent of the original rock

History

Origin

Germany

New Zealand

Discoverer

Van Tooren

Unknown

Etymology

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

From German which means hornstone

Class

Igneous Rocks

Metamorphic Rocks

Sub-Class

Durable Rock, Hard Rock

Durable Rock, Soft 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

Granular, Platy

Color

Black, Brown, Green, Grey, White

Brown, Dark Greenish - Grey, Green, Reddish Brown

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Vesicular

Dull

Uses

Architecture

Interior Uses

Decorative Aggregates, Flooring, Homes, Interior Decoration

Exterior Uses

As Building Stone, As Facing Stone, Garden Decoration, Office Buildings

As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone

Other Architectural Uses

Curbing

Industry

Construction Industry

Landscaping

for Road Aggregate, Roadstone

Medical Industry

Antiquity Uses

Artifacts, Sculpture

Artifacts, Monuments

Other Uses

Commercial Uses

Production of Lime, Soil Conditioner

Cemetery Markers, Commemorative Tablets, Creating Artwork

Types

Igneous rock

Biotite hornfels

Features

Host Rock for Lead

Smooth to touch

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.

Due to change in environmental conditions, rocks are heated and pressurized deep inside the Earth's surface. Hornfels is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.

Composition

Mineral Content

Alkali feldspar, Nepheline, Plagioclase, Pyroxene

Andalusite

Compound Content

CaO, Carbon Dioxide, MgO, Silicon Dioxide

Fe, Mg

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Cataclastic Metamorphism, Contact 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, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion

Properties

Physical Properties

Hardness

6.52-3

1 7

👆🏻

Grain Size

Medium to Fine Coarse Grained

Fine Grained

Fracture

Uneven

Conchoidal

Streak

Bluish Black

Porosity

Very Less Porous

Highly Porous

Luster

Subvitreous to Dull

Shiny

Compressive Strength

90.00 N/mm²5.80 N/mm²

0.15 450

👆🏻

Cleavage

Crenulation and Pervasive

Perfect

Toughness

2.4

Specific Gravity

2.863.4-3.9

0 8.4

👆🏻

Transparency

Opaque

Density

2.8-2.9 g/cm³0.25-0.30 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.92 kJ/Kg K0.84 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant

Heat Resistant, Impact Resistant, Pressure Resistant

Reserves

Deposits in Eastern Continents

Asia

Bangladesh, Bhutan, China, India, North Korea, Qatar, Russia, Saudi Arabia, South Korea, Thailand

Africa

Namibia, Uganda

Cameroon, East Africa, Tanzania, Western Africa

Europe

Germany, Hungary, Italy, Portugal, Spain

United Kingdom

Others

Deposits in Western Continents

North America

USA

Canada, USA

South America

Bolivia, Brazil, Colombia, Ecuador

Deposits in Oceania Continent

Australia

New Zealand, Western Australia

New South Wales, New Zealand, Queensland, Western Australia

All about Tephrite and Hornfels Properties

Know all about Tephrite and Hornfels properties here. All properties of rocks are important as they define the type of rock and its application. Tephrite belongs to Igneous Rocks while Hornfels belongs to Metamorphic Rocks.Texture of Tephrite is Aphanitic to Porphyritic whereas that of Hornfels is Granular, Platy. Tephrite appears Vesicular and Hornfels appears Dull. The luster of Tephrite is subvitreous to dull while that of Hornfels is shiny. Tephrite is available in black, brown, green, grey, white colors whereas Hornfels is available in brown, dark greenish - grey, green, reddish brown colors. The commercial uses of Tephrite are production of lime, soil conditioner and that of Hornfels are cemetery markers, commemorative tablets, creating artwork.