Variolite

Lignite

Variolite and Lignite

Variolite

Lignite

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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

Lignite is a soft brownish coal which shows traces of plants and is intermediate between bituminous coal and peat

History

Origin

France

Discoverer

Unknown

Etymology

From Latin varius, speckled, variegated

From French, Latin lignum wood + -ite1

Class

Igneous Rocks

Sedimentary Rocks

Sub-Class

Durable Rock, Hard Rock

Durable Rock, Soft Rock

Family

Group

Volcanic

Other Categories

Opaque Rock

Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock

Texture

Glassy, Massive, Porphyritic, Scoriaceous, Vesicular

Amorphous, Glassy

Color

Black, Brown, Light to Dark Grey

Black, Brown, Dark Brown, Grey, Light to Dark Grey

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull and Soft

Veined or Pebbled

Uses

Architecture

Interior Uses

Floor Tiles, Flooring, Homes, Hotels, Kitchens

Exterior Uses

Garden Decoration, Office Buildings

Other Architectural Uses

Curbing

Industry

Construction Industry

As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone

for Road Aggregate, Steel Production

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture

Other Uses

Commercial Uses

Cemetery Markers, Creating Artwork

Electricity Generation

Types

Metamorphic rock

Xyloid Lignite or Fossil Wood and Compact Lignite or Perfect Lignite

Features

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

Generally rough to touch, Helps in production of Heat and Electricity, Used as fossil fuel

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.

Coal formation takes place due to accumulation of plant debris in a swamp environment. The Coal formation process continues, as peat turns into lignite brown or black coal at increasing heat and pressure.

Composition

Mineral Content

Olivine, Plagioclase, Pyroxene

Compound Content

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

Carbon, Hydrogen, Nitrogen, Oxygen, Sulphur

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

Chemical Erosion, Water Erosion, Wind Erosion

Properties

Physical Properties

Hardness

1 7

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Grain Size

Medium to Fine Coarse Grained

Fracture

Conchoidal

Streak

White to Grey

Black

Porosity

Less Porous

Highly Porous

Luster

Dull to Vitreous to Submetallic

Compressive Strength

37.50 N/mm²-

0.15 450

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Cleavage

Toughness

2.3

Specific Gravity

2.8-31.1-1.4

0 8.4

👆🏻

Transparency

Opaque

Density

2.9-3.1 g/cm³800-801 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.84 kJ/Kg K1.26 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Pressure Resistant, Wear Resistant

Heat Resistant

Reserves

Deposits in Eastern Continents

Asia

India, Russia

Bangladesh, Burma, Cambodia, China, India, Indonesia, Kazakhstan, Malaysia, Mongolia, Pakistan, Turkey, Vietnam

Africa

South Africa

Botswana, Kenya, Morocco, Mozambique, South Africa, Tanzania

Europe

Iceland

Belgium, Bulgaria, England, France, Germany, Greece, Hungary, Kosovo, Netherlands, Norway, Poland, Romania, Serbia, Slovakia, Slovenia, The Czech Republic, Ukraine, United Kingdom

Others

Deposits in Western Continents

North America

Canada, USA

Canada, Mexico, USA

South America

Brazil

Brazil, Chile, Colombia, Venezuela

Deposits in Oceania Continent

Australia

New South Wales, Queensland, Victoria

All about Variolite and Lignite Properties

Know all about Variolite and Lignite properties here. All properties of rocks are important as they define the type of rock and its application. Variolite belongs to Igneous Rocks while Lignite belongs to Sedimentary Rocks.Texture of Variolite is Glassy, Massive, Porphyritic, Scoriaceous, Vesicular whereas that of Lignite is Amorphous, Glassy. Variolite appears Dull and Soft and Lignite appears Veined or Pebbled. The luster of Variolite is while that of Lignite is dull to vitreous to submetallic. Variolite is available in black, brown, light to dark grey colors whereas Lignite is available in black, brown, dark brown, grey, light to dark grey colors. The commercial uses of Variolite are cemetery markers, creating artwork and that of Lignite are electricity generation.