Variolite

Arkose

Variolite and Arkose

Variolite

Arkose

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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

Arkose is a sedimentary rock, specifically a type of sandstone containing at least 25% feldspar

History

Origin

France

Discoverer

Unknown

Alexandre Brongniart

Etymology

From Latin varius, speckled, variegated

From Auvergne region of France used by a French geologist Alexandre Brongniart in 1826 who applied this term to some feldspathic sandstones

Class

Igneous Rocks

Sedimentary Rocks

Sub-Class

Durable Rock, Hard Rock

Family

Group

Volcanic

Other Categories

Opaque Rock

Coarse Grained Rock, Opaque Rock

Texture

Glassy, Massive, Porphyritic, Scoriaceous, Vesicular

Clastic

Color

Black, Brown, Light to Dark Grey

Reddish Brown

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

Paving Stone, Office Buildings

Other Architectural Uses

Curbing

Whetstones

Industry

Construction Industry

As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone

Cement Manufacture, Construction Aggregate, for Road Aggregate, Production of Glass and Ceramics, Raw material for the manufacture of mortar

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture

Artifacts, Sculpture, Small Figurines

Other Uses

Commercial Uses

Cemetery Markers, Creating Artwork

In aquifers, Soil Conditioner, Source of Magnesia (MgO), Tombstones

Types

Metamorphic rock

Arkose

Features

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

Available in Lots of Colors and Patterns, Generally rough to touch, 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.

Arkose rock forms from the weathering of feldspar-rich igneous or metamorphic rock, most commonly granitic rocks, which are primarily composed of quartz and feldspar.

Composition

Mineral Content

Olivine, Plagioclase, Pyroxene

Calcite, Clay, Clay Minerals, Feldspar, Micas, Quartz

Compound Content

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

Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, 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

Erosion

✔ ✘

Types of Erosion

Coastal Erosion, Glacier Erosion, Water Erosion, Wind Erosion

Properties

Physical Properties

Hardness

66-7

1 7

👆🏻

Grain Size

Coarse Grained

Fracture

Conchoidal

Streak

White to Grey

White

Porosity

Less Porous

Highly Porous

Luster

Dull

Compressive Strength

37.50 N/mm²80.00 N/mm²

0.15 450

👆🏻

Cleavage

Toughness

2.3

Specific Gravity

2.8-30

0 8.4

👆🏻

Transparency

Opaque

Density

2.9-3.1 g/cm³-9999 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.84 kJ/Kg K0.78 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Pressure Resistant, Wear Resistant

Heat Resistant, Impact Resistant, Pressure Resistant

Reserves

Deposits in Eastern Continents

Asia

India, Russia

China, India, Kazakhstan, Mongolia, Russia, Uzbekistan

Africa

South Africa

Namibia, Nigeria, South Africa

Europe

Iceland

Austria, Denmark, Germany, Great Britain, Netherlands, Norway, Poland, Sweden, Switzerland, United Kingdom

Others

Greenland

Deposits in Western Continents

North America

Canada, USA

South America

Brazil

Deposits in Oceania Continent

Australia

New South Wales, New Zealand

All about Variolite and Arkose Properties

Know all about Variolite and Arkose properties here. All properties of rocks are important as they define the type of rock and its application. Variolite belongs to Igneous Rocks while Arkose belongs to Sedimentary Rocks.Texture of Variolite is Glassy, Massive, Porphyritic, Scoriaceous, Vesicular whereas that of Arkose is Clastic. Variolite appears Dull and Soft and Arkose appears Rough and Dull. The luster of Variolite is while that of Arkose is dull. Variolite is available in black, brown, light to dark grey colors whereas Arkose is available in reddish brown colors. The commercial uses of Variolite are cemetery markers, creating artwork and that of Arkose are in aquifers, soil conditioner, source of magnesia (mgo), tombstones.