Arkose

Obsidian

Arkose and Obsidian

Arkose

Obsidian

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Definition

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

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

History

Origin

France

Ethiopia

Discoverer

Alexandre Brongniart

Obsius

Etymology

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

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

Class

Sedimentary Rocks

Igneous Rocks

Sub-Class

Durable Rock, Hard Rock

Durable Rock, Medium Hardness Rock

Family

Group

Volcanic

Other Categories

Coarse Grained Rock, Opaque Rock

Opaque Rock

Texture

Clastic

Glassy

Color

Reddish Brown

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

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Rough and Dull

Shiny

Uses

Architecture

Interior Uses

Decorative Aggregates, Homes, Interior Decoration

Decorative Aggregates, Interior Decoration

Exterior Uses

Paving Stone, Office Buildings

Garden Decoration

Other Architectural Uses

Whetstones

Industry

Construction Industry

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

Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points

Medical Industry

Surgery

Antiquity Uses

Artifacts, Sculpture, Small Figurines

Artifacts, Jewellery

Other Uses

Commercial Uses

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

Creating Artwork, Mirror, Used in aquariums

Types

Arkose

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

Features

Available in Lots of Colors and Patterns, Generally rough to touch, Is one of the oldest rock

Blocks negativity, Helps to protect against depression

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Present

Absent

Formation

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.

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.

Composition

Mineral Content

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

Compound Content

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

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

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Coastal Erosion, Glacier Erosion, Water Erosion, Wind Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Properties

Physical Properties

Hardness

6-75-5.5

1 7

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Grain Size

Coarse Grained

Fracture

Conchoidal

Streak

White

Porosity

Highly Porous

Very Less Porous

Luster

Dull

Vitreous

Compressive Strength

80.00 N/mm²0.15 N/mm²

0.15 450

👆🏻

Cleavage

Toughness

Specific Gravity

02.6-2.7

0 8.4

👆🏻

Transparency

Opaque

Translucent

Density

-9999 g/cm³2.6 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.78 kJ/Kg K0.92 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant

Heat Resistant, Impact Resistant

Reserves

Deposits in Eastern Continents

Asia

China, India, Kazakhstan, Mongolia, Russia, Uzbekistan

Afghanistan, Indonesia, Japan, Russia

Africa

Namibia, Nigeria, South Africa

Kenya

Europe

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

Greece, Hungary, Iceland, Italy, Turkey

Others

Greenland

Deposits in Western Continents

North America

Canada, USA

Canada, Mexico, USA

South America

Brazil

Argentina, Chile, Ecuador, Peru

Deposits in Oceania Continent

Australia

New South Wales, New Zealand

New Zealand

All about Arkose and Obsidian Properties

Know all about Arkose and Obsidian properties here. All properties of rocks are important as they define the type of rock and its application. Arkose belongs to Sedimentary Rocks while Obsidian belongs to Igneous Rocks.Texture of Arkose is Clastic whereas that of Obsidian is Glassy. Arkose appears Rough and Dull and Obsidian appears Shiny. The luster of Arkose is dull while that of Obsidian is vitreous. Arkose is available in reddish brown colors whereas Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors. The commercial uses of Arkose are in aquifers, soil conditioner, source of magnesia (mgo), tombstones and that of Obsidian are creating artwork, mirror, used in aquariums.