Variolite

Argillite

Variolite and Argillite

Variolite

Argillite

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Definition

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

Argillites are highly compact sedimentary or slightly metamorphosed rocks that consist largely or wholly of particles of clay or silt but lack the fissility of shale or the cleavage characteristic of slate

History

Origin

France

Discoverer

Unknown

Etymology

From Latin varius, speckled, variegated

From Latin Argilla (clay) and -ite in English which became agrilla+ -ite = Argillite

Class

Igneous Rocks

Sedimentary Rocks

Sub-Class

Durable Rock, Hard Rock

Durable Rock, Soft Rock

Family

Group

Volcanic

Other Categories

Opaque Rock

Fine Grained Rock, Opaque Rock

Texture

Glassy, Massive, Porphyritic, Scoriaceous, Vesicular

Clastic, Polished

Color

Black, Brown, Light to Dark Grey

Dark Grey to Black, Pink, Red, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull and Soft

Rough and Dull

Uses

Architecture

Interior Uses

Floor Tiles, Flooring, Homes, Hotels, Kitchens

Decorative Aggregates, Homes, Interior Decoration

Exterior Uses

Garden Decoration, Office Buildings

As Building Stone, Garden Decoration, Office Buildings

Other Architectural Uses

Curbing

Curbing, Whetstones

Industry

Construction Industry

As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone

Used for flooring, stair treads, borders and window sills.

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture

Other Uses

Commercial Uses

Cemetery Markers, Creating Artwork

Fire resistant, Used to manufracture paperweights and bookends

Types

Metamorphic rock

Features

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

Is one of the oldest rock

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Present

Formation

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

An argillite is a fine-grained sedimentary rock mainly composed of clay particles which forms from lithified muds which contain variable amounts of silt-sized particles.

Composition

Mineral Content

Olivine, Plagioclase, Pyroxene

Biotite, Chlorite, Feldspar, Micas, Muscovite or Illite, Plagioclase, Pyrite, Quartz

Compound Content

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

Iron(III) Oxide, Potassium Oxide, MgO, Silicon Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

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

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Biological Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion

Properties

Physical Properties

Hardness

62-3

1 7

👆🏻

Grain Size

Fine Grained

Fracture

Conchoidal

Conchoidal to Uneven

Streak

White to Grey

Porosity

Less Porous

Highly Porous

Luster

Waxy and Dull

Compressive Strength

37.50 N/mm²-

0.15 450

👆🏻

Cleavage

Slaty

Toughness

2.3

2.6

Specific Gravity

2.8-32.56-2.68

0 8.4

👆🏻

Transparency

Opaque

Density

2.9-3.1 g/cm³2.54-2.66 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.84 kJ/Kg K0.87 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Pressure Resistant, Wear Resistant

Heat Resistant, Impact Resistant

Reserves

Deposits in Eastern Continents

Asia

India, Russia

Bangladesh, China, India, Russia

Africa

South Africa

Ethiopia, Kenya, Morocco, South Africa, Tanzania

Europe

Iceland

Austria, France, Germany, Greece, Italy, Romania, Scotland, Spain, Switzerland

Others

Deposits in Western Continents

North America

Canada, USA

USA

South America

Brazil

Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela

Deposits in Oceania Continent

Australia

New South Wales, New Zealand, Queensland, Victoria, Western Australia

All about Variolite and Argillite Properties

Know all about Variolite and Argillite properties here. All properties of rocks are important as they define the type of rock and its application. Variolite belongs to Igneous Rocks while Argillite belongs to Sedimentary Rocks.Texture of Variolite is Glassy, Massive, Porphyritic, Scoriaceous, Vesicular whereas that of Argillite is Clastic, Polished. Variolite appears Dull and Soft and Argillite appears Rough and Dull. The luster of Variolite is while that of Argillite is waxy and dull. Variolite is available in black, brown, light to dark grey colors whereas Argillite is available in dark grey to black, pink, red, white colors. The commercial uses of Variolite are cemetery markers, creating artwork and that of Argillite are fire resistant, used to manufracture paperweights and bookends.