Obsidian

Anthracite

Obsidian vs Anthracite

Obsidian

Anthracite

Add ⊕

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

Anthracite is a type of sedimentary rock which is hard and is variety of coal that has high luster

History

Origin

Ethiopia

Pennsylvania, U.S.

Discoverer

Obsius

Unknown

Etymology

From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius

From Greek anthrakites, from anthrax, anthrak meaning coal

Class

Igneous Rocks

Metamorphic 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

Glassy

Amorphous, Glassy

Color

Black, Blue, Brown, Green, Orange, Red, Tan, Yellow

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

Maintenance

Less

Durability

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

In Chemical and Pharmaceutical Industry, Manufacture of Aspirins

Antiquity Uses

Artifacts, Jewellery

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

Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian

Semi-anthracite and Meta-anthracite

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

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.

Anthracite forms from the accumulation of plant debris in a swamp environment. When plant debris dies and falls into the swamp, the standing water of the swamp protects it from decay.

Composition

Mineral Content

Calcite, Clay, Clay Minerals

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, Contact 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

Streak

White

Black

Porosity

Very Less Porous

Less Porous

Luster

Vitreous

Shiny

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/cm³1.25-2.5 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, Water 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

South America

Argentina, Chile, Ecuador, Peru

Brazil, Chile, Colombia, Venezuela

Deposits in Oceania Continent

Australia

New Zealand

New South Wales, Queensland, Victoria

Obsidian vs Anthracite 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 Anthracite 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. Anthracite is a type of sedimentary rock which is hard and is variety of coal that has high luster. 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 Anthracite information and Obsidian vs Anthracite characteristics in the upcoming sections.

Compare Igneous Rocks » More

Obsidian vs Andesite

Obsidian vs Scoria

Obsidian vs Peridotite

» More Compare Igneous Rocks

Obsidian vs Anthracite 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 Anthracite characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Obsidian and Properties of Anthracite. Learn more about Obsidian vs Anthracite in the next section. The interior uses of Obsidian include Decorative aggregates and Interior decoration whereas the interior uses of Anthracite include . Due to some exceptional properties of Obsidian and Anthracite, 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 Anthracite include Cement manufacture, For road aggregate, Making natural cement, Steel production.

More about Obsidian and Anthracite

Here you can know more about Obsidian and Anthracite. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Obsidian and Anthracite consists of mineral content and compound content. The mineral content of Obsidian includes and mineral content of Anthracite includes Calcite, Clay, Clay Minerals. You can also check out the list of all Igneous Rocks. When we have to compare Obsidian vs Anthracite, 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, Anthracite is available in black, brown, dark brown, grey, light to dark grey colors. Appearance of Obsidian is Shiny and that of Anthracite is Veined or Pebbled. Properties of rock is another aspect for Obsidian vs Anthracite. The hardness of Obsidian is 5-5.5 and that of Anthracite is 1-1.5. The types of Obsidian are Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian whereas types of Anthracite are Semi-anthracite and Meta-anthracite. 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 Anthracite is black. The specific heat capacity of Obsidian is 0.92 kJ/Kg K and that of Anthracite 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 Anthracite is heat resistant, water resistant.