Ignimbrite

Variolite

Ignimbrite and Variolite

Ignimbrite

Variolite

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Definition

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

Variolites are a group of dark green basic igneous rocks which exhibit pale colored spots, or spherules, especially on weathered surfaces, that give them a pockmarked appearance

History

Origin

New Zealand

France

Discoverer

Patrick Marshall

Unknown

Etymology

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

From Latin varius, speckled, variegated

Class

Igneous Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Durable Rock, Hard Rock

Family

Group

Volcanic

Other Categories

Fine Grained Rock, Opaque Rock

Opaque Rock

Texture

Aphanitic

Glassy, Massive, Porphyritic, Scoriaceous, Vesicular

Color

Beige, Black, Brown, Grey, Pink, White

Black, Brown, Light to Dark Grey

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull, Vesicular and Foilated

Dull and Soft

Uses

Architecture

Interior Uses

Decorative Aggregates, Floor Tiles, Homes, Interior Decoration

Floor Tiles, Flooring, Homes, Hotels, Kitchens

Exterior Uses

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

Garden Decoration, Office Buildings

Other Architectural Uses

Curbing

Industry

Construction Industry

Building houses or walls, Construction Aggregate

As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture, Small Figurines

Artifacts, Monuments, Sculpture

Other Uses

Commercial Uses

Cemetery Markers, Commemorative Tablets, Creating Artwork

Cemetery Markers, Creating Artwork

Types

Pyroclastic rock

Metamorphic rock

Features

Always found as volcanic pipes over deep continental crust

Has High structural resistance against erosion and climate, Very fine grained rock

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Formation

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

Variolites are a group of dark green basic igneous rocks that exhibit pale colored spots on weathered surfaces that give them a pockmarked appearance.

Composition

Mineral Content

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

Olivine, Plagioclase, Pyroxene

Compound Content

Ca, NaCl

Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

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

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

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Coastal Erosion

Properties

Physical Properties

Hardness

4-66

1 7

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Grain Size

Fine Grained

Fracture

Uneven

Conchoidal

Streak

White

White to Grey

Porosity

Highly Porous

Less Porous

Luster

Vitreous to Dull

Compressive Strength

243.80 N/mm²37.50 N/mm²

0.15 450

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Cleavage

Toughness

2.3

Specific Gravity

2.732.8-3

0 8.4

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Transparency

Opaque

Density

1-1.8 g/cm³2.9-3.1 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.20 kJ/Kg K0.84 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Heat Resistant, Pressure Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

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

India, Russia

Africa

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

South Africa

Europe

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

Iceland

Others

Antarctica, Hawaii Islands

Deposits in Western Continents

North America

Canada, Costa Rica, Panama, USA

Canada, USA

South America

Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador

Brazil

Deposits in Oceania Continent

Australia

Central Australia, Western Australia

All about Ignimbrite and Variolite Properties

Know all about Ignimbrite and Variolite properties here. All properties of rocks are important as they define the type of rock and its application. Ignimbrite and Variolite belong to Igneous Rocks.Texture of Ignimbrite is Aphanitic whereas that of Variolite is Glassy, Massive, Porphyritic, Scoriaceous, Vesicular. Ignimbrite appears Dull, Vesicular and Foilated and Variolite appears Dull and Soft. The luster of Ignimbrite is vitreous to dull while that of Variolite is . Ignimbrite is available in beige, black, brown, grey, pink, white colors whereas Variolite is available in black, brown, light to dark grey colors. The commercial uses of Ignimbrite and Variolite are cemetery markers, commemorative tablets, creating artwork.