Hornfels

Ignimbrite

Hornfels and Ignimbrite

Hornfels

Ignimbrite

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Definition

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

Ignimbrite is a volcanic rock consisting mainly of pumice fragments, formed by the consolidation of material deposited by pyroclastic flows

History

Origin

New Zealand

Discoverer

Unknown

Patrick Marshall

Etymology

From German which means hornstone

From Latin ignis fire + imber, imbr- shower of rain, storm cloud + -ite

Class

Metamorphic Rocks

Igneous Rocks

Sub-Class

Durable Rock, Soft Rock

Durable Rock, Medium Hardness Rock

Family

Group

Volcanic

Other Categories

Fine Grained Rock, Opaque Rock

Texture

Granular, Platy

Aphanitic

Color

Brown, Dark Greenish - Grey, Green, Reddish Brown

Beige, Black, Brown, Grey, Pink, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull

Dull, Vesicular and Foilated

Uses

Architecture

Interior Uses

Decorative Aggregates, Flooring, Homes, Interior Decoration

Decorative Aggregates, Floor Tiles, Homes, Interior Decoration

Exterior Uses

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

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

Other Architectural Uses

Curbing

Industry

Construction Industry

for Road Aggregate, Roadstone

Building houses or walls, Construction Aggregate

Medical Industry

Antiquity Uses

Artifacts, Monuments

Artifacts, Monuments, Sculpture, Small Figurines

Other Uses

Commercial Uses

Cemetery Markers, Commemorative Tablets, Creating Artwork

Types

Biotite hornfels

Pyroclastic rock

Features

Smooth to touch

Always found as volcanic pipes over deep continental crust

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Formation

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.

Ignimbrites are formed from very poorly sorted mixture of volcanic ash or tuff and pumice lapilli, commonly with scattered lithic fragments.

Composition

Mineral Content

Andalusite

Apatite, Biotite, Calcite, Chlorite, Feldspar, Hematite, Hornblade, Ilmenite, Magnetite, Olivine, Pyroxene, Quartz

Compound Content

Fe, Mg

Ca, NaCl

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering

Biological Weathering, Chemical Weathering

Erosion

✔ ✘

Types of Erosion

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

Chemical Erosion, Coastal Erosion

Properties

Physical Properties

Hardness

2-34-6

1 7

👆🏻

Grain Size

Fine Grained

Fracture

Conchoidal

Uneven

Streak

White

Porosity

Highly Porous

Luster

Shiny

Vitreous to Dull

Compressive Strength

5.80 N/mm²243.80 N/mm²

0.15 450

👆🏻

Cleavage

Perfect

Toughness

Specific Gravity

3.4-3.92.73

0 8.4

👆🏻

Transparency

Opaque

Density

0.25-0.30 g/cm³1-1.8 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.84 kJ/Kg K0.20 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

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

Afghanistan, Armenia, Azerbaijan, Burma, Cambodia, China, India, Indonesia, Iran, Japan, Malaysia, Mongolia, Nepal, North Korea, Pakistan, Saudi Arabia, Syria, Taiwan, Thailand, Turkey, Vietnam, Yemen

Africa

Cameroon, East Africa, Tanzania, Western Africa

Cameroon, Cape Verde, Chad, Djibouti, Eritrea, Ethiopia, Kenya, Libya, Madagascar, Nigeria, Rwanda, South Africa, Sudan, Tanzania, Uganda

Europe

United Kingdom

France, Georgia, Germany, Greece, Iceland, Italy, Netherlands, Poland, Portugal, Spain, United Kingdom

Others

Antarctica, Hawaii Islands

Deposits in Western Continents

North America

Canada, USA

Canada, Costa Rica, Panama, USA

South America

Bolivia, Brazil, Colombia, Ecuador

Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador

Deposits in Oceania Continent

Australia

New South Wales, New Zealand, Queensland, Western Australia

Central Australia, Western Australia

All about Hornfels and Ignimbrite Properties

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