Obsidian

Siltstone

Obsidian and Siltstone

Obsidian

Siltstone

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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

Siltstone can be defined as a fine-grained sedimentary rock which mainly consists of consolidated silt

History

Origin

Ethiopia

Discoverer

Obsius

Unknown

Etymology

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

From English word silt and stone and from Proto-Indo-European root sal and stainaz

Class

Igneous Rocks

Sedimentary Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Durable Rock, Hard Rock

Family

Group

Volcanic

Other Categories

Opaque Rock

Fine Grained Rock, Opaque Rock

Texture

Glassy

Clastic

Color

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

Brown, Red, Reddish Brown

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Shiny

Rough

Uses

Architecture

Interior Uses

Decorative Aggregates, Interior Decoration

Exterior Uses

Garden Decoration

As Building Stone, As Facing Stone, Garden Decoration

Other Architectural Uses

Curbing

Industry

Construction Industry

Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points

Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate, Making natural cement, Raw material for the manufacture of mortar

Medical Industry

Surgery

Antiquity Uses

Artifacts, Jewellery

Artifacts, Sculpture, Small Figurines

Other Uses

Commercial Uses

Creating Artwork, Mirror, Used in aquariums

Raw material for the manufacture of mortar, Soil Conditioner

Types

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

Siltstone

Features

Blocks negativity, Helps to protect against depression

Available in Lots of Colors and Patterns, Easily splits into thin plates, Generally rough to touch, High silica content, Very fine grained rock

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Present

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.

Siltstone is a type of sedimentary rock which is formed from fine rock particles. As the particles of eroded rock travel along with water, the edges of the rock are worn-out by water into a rounded shape.

Composition

Mineral Content

Calcite, Clay, Clay Minerals, Feldspar, Micas, Quartz, Sand, Silica, Silt

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

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Properties

Physical Properties

Hardness

5-5.56-7

1 7

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Grain Size

Fine Grained

Fracture

Conchoidal

Streak

White

Porosity

Very Less Porous

Highly Porous

Luster

Vitreous

Dull

Compressive Strength

0.15 N/mm²30.00 N/mm²

0.15 450

👆🏻

Cleavage

Toughness

2.6

Specific Gravity

2.6-2.72.54-2.73

0 8.4

👆🏻

Transparency

Translucent

Opaque

Density

2.6 g/cm³2.6-2.7 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.92 kJ/Kg K0.84 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant

Heat Resistant, Impact Resistant, Pressure Resistant, Water Resistant

Reserves

Deposits in Eastern Continents

Asia

Afghanistan, Indonesia, Japan, Russia

China, India, Kazakhstan, Mongolia, Russia, Uzbekistan

Africa

Kenya

Namibia, Nigeria, South Africa

Europe

Greece, Hungary, Iceland, Italy, Turkey

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

Others

Greenland

Deposits in Western Continents

North America

Canada, Mexico, USA

Canada, USA

South America

Argentina, Chile, Ecuador, Peru

Brazil

Deposits in Oceania Continent

Australia

New Zealand

New South Wales, New Zealand

All about Obsidian and Siltstone Properties

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