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Obsidian
Obsidian

Coal
Coal



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Obsidian vs Coal

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Definition

Definition

Obsidian is a naturally occurring volcanic glass formed as an extrusive igneous rock. It is produced when felsic lava extruded from a volcano cools rapidly with minimum crystal growth
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers called coal beds

History

Origin

Ethiopia
USA

Discoverer

Obsius
John Peter Salley

Etymology

From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius
From the Old English term col, which has meant mineral of fossilized carbon since the 13th century

Class

Igneous Rocks
Sedimentary Rocks

Sub-Class

Durable Rock, Medium Hardness Rock
Durable Rock, Soft Rock

Family

Group

Volcanic
-

Other Categories

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

Texture

Texture

Glassy
Amorphous, Glassy

Color

Black, Blue, Brown, Green, Orange, Red, Tan, Yellow
Black, Brown, Dark Brown, Grey, Light to Dark Grey

Maintenance

Less
Less

Durability

Durable
Durable

Water Resistant

Scratch Resistant

Stain Resistant

Wind Resistant

Acid Resistant

Appearance

Shiny
Veined or Pebbled

Uses

Architecture

Interior Uses

Decorative Aggregates, Interior Decoration
-

Exterior Uses

Garden Decoration
-

Other Architectural Uses

-
-

Industry

Construction Industry

Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points
Cement Manufacture, for Road Aggregate, Making natural cement, Steel Production

Medical Industry

Surgery
-

Antiquity Uses

Artifacts, Jewellery
Artifacts

Other Uses

Commercial Uses

Creating Artwork, Mirror, Used in aquariums
Alumina Refineries, Electricity Generation, Liquid Fuel, Manufacture of Soap, Solvents, Dyes, Plastics and Fibres, Paper Industry

Types

Types

Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian
Peat, Lignite, Sub-Bituminous Coal, Bituminous Coal, Anthracite, Graphite

Features

Blocks negativity, Helps to protect against depression
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

Formation

When the lava is released from volcano, it undergoes a very rapid cooling which freezes the mechanisms of crystallization. The result is a volcanic glass with a uniform smooth texture.
Coal forms from the accumulation of plant debris in a swamp environment which is buried by sediments such as mud or sand and then compacted to form coal.

Composition

Mineral Content

-
Analcime, Apatite, Barite, Calcite, Chalcopyrite, Chlorite, Chromite, Clausthalite, Clay Minerals, Crandallite Group, Dolomite, Feldspar, Galena, Gypsum, Marcasite, Muscovite or Illite, Pyrite, Quartz, Siderite, Sphalerite, Zircon

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
Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism

Weathering

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering
-

Erosion

Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion
-

Properties

Physical Properties

Hardness

5-5.51-1.5
1 7
👆🏻

Grain Size

-
Medium to Fine Coarse Grained

Fracture

Conchoidal
Conchoidal

Streak

White
Black

Porosity

Very Less Porous
Less Porous

Luster

Vitreous
Dull to Vitreous to Submetallic

Compressive Strength

0.15 N/mm2-
0.15 450
👆🏻

Cleavage

-
-

Toughness

-
-

Specific Gravity

2.6-2.71.1-1.4
0 8.4
👆🏻

Transparency

Translucent
Opaque

Density

2.6 g/cm31100-1400 g/cm3
0 1400
👆🏻

Thermal Properties

Specific Heat Capacity

0.92 kJ/Kg K1.32 kJ/Kg K
0.14 3.2
👆🏻

Resistance

Heat Resistant, Impact Resistant
Heat Resistant

Reserves

Deposits in Eastern Continents

Asia

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

Africa

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

Europe

Greece, Hungary, Iceland, Italy, Turkey
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, Mexico, USA
Canada, Mexico, USA

South America

Argentina, Chile, Ecuador, Peru
Brazil, Chile, Colombia, Venezuela

Deposits in Oceania Continent

Australia

New Zealand
New South Wales, Queensland, Victoria

Obsidian vs Coal Information

Earth’s outer layer is covered by rocks and these rocks have different physical and chemical properties. As two rocks are not same, it’s fun to compare them. You can also know more about Obsidian and Coal Reserves. Obsidian is a naturally occurring volcanic glass formed as an extrusive igneous rock. It is produced when felsic lava extruded from a volcano cools rapidly with minimum crystal growth. Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers called coal beds. These rocks are composed of many distinct minerals. The process of formation of rocks is different for various rocks. Rocks are quarried from many years for various purposes. You can check out Obsidian vs Coal information and Obsidian vs Coal characteristics in the upcoming sections.

Obsidian vs Coal Characteristics

Though some rocks look identical, they have certain characteristics which distinguish them from others. Characteristics of rocks include texture, appearance, color, fracture, streak, hardness etc. Obsidian vs Coal characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Obsidian and Properties of Coal. Learn more about Obsidian vs Coal in the next section. The interior uses of Obsidian include Decorative aggregates and Interior decoration whereas the interior uses of Coal include . Due to some exceptional properties of Obsidian and Coal, they have various applications in construction industry. The uses of Obsidian in construction industry include Arrowheads, Cutting tool, Knives, Scrapers, Spear points and that of Coal include Cement manufacture, For road aggregate, Making natural cement, Steel production.

More about Obsidian and Coal

Here you can know more about Obsidian and Coal. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Obsidian and Coal consists of mineral content and compound content. The mineral content of Obsidian includes and mineral content of Coal includes Analcime, Apatite, Barite, Calcite, Chalcopyrite, Chlorite, Chromite, Clausthalite, Clay Minerals, Crandallite Group, Dolomite, Feldspar, Galena, Gypsum, Marcasite, Muscovite or Illite, Pyrite, Quartz, Siderite, Sphalerite, Zircon. You can also check out the list of all Igneous Rocks. When we have to compare Obsidian vs Coal, the texture, color and appearance plays an important role in determining the type of rock. Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors whereas, Coal is available in black, brown, dark brown, grey, light to dark grey colors. Appearance of Obsidian is Shiny and that of Coal is Veined or Pebbled. Properties of rock is another aspect for Obsidian vs Coal. The hardness of Obsidian is 5-5.5 and that of Coal is 1-1.5. The types of Obsidian are Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian whereas types of Coal are Peat, Lignite, Sub-Bituminous Coal, Bituminous Coal, Anthracite, Graphite. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Obsidian is white while that of Coal is black. The specific heat capacity of Obsidian is 0.92 kJ/Kg K and that of Coal is 1.32 kJ/Kg K. Depending on the properties like hardness, toughness, specific heat capacity, porosity etc., rocks are resistant to heat, wear, impact, etc.Obsidian is heat resistant, impact resistant whereas Coal is heat resistant.