Schist

Obsidian

Schist and Obsidian

Schist

Obsidian

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1 Definition

1.1 Definition

Schist is a medium grade metamorphic rock with medium to large, flat, sheet like grains in a preferred orientation

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

1.2 History

1.2.1 Origin

Unknown

Ethiopia

1.2.2 Discoverer

Unknown

Obsius

1.3 Etymology

From French schiste, Greek skhistos i.e. split

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

1.4 Class

Metamorphic Rocks

Igneous Rocks

1.4.1 Sub-Class

Durable Rock, Medium Hardness Rock

1.5 Family

1.5.1 Group

Not Applicable

Volcanic

1.6 Other Categories

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

Opaque Rock

2 Texture

2.1 Texture

Foliated, Platy

Glassy

2.2 Color

Black, Blue, Brown, Dark Brown, Green, Grey, Silver

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

2.3 Maintenance

Less

2.4 Durability

Durable

2.4.1 Water Resistant

✔ ✘

2.4.2 Scratch Resistant

✔ ✘

2.4.3 Stain Resistant

✔ ✘

2.4.4 Wind Resistant

✔ ✘

2.4.5 Acid Resistant

✔ ✘

2.5 Appearance

Layered and Shiny

Shiny

3 Uses

3.1 Architecture

3.1.1 Interior Uses

Decorative Aggregates, Floor Tiles, Interior Decoration

Decorative Aggregates, Interior Decoration

3.1.2 Exterior Uses

Garden Decoration, Paving Stone

Garden Decoration

3.1.3 Other Architectural Uses

Not Yet Used

3.2 Industry

3.2.1 Construction Industry

As Dimension Stone, Building houses or walls, Cement Manufacture, for Road Aggregate, Roadstone

Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points

3.2.2 Medical Industry

Not Yet Used

Surgery

3.3 Antiquity Uses

Artifacts

Artifacts, Jewellery

3.4 Other Uses

3.4.1 Commercial Uses

Used in aquariums, Writing Slates

Creating Artwork, Mirror, Used in aquariums

4 Types

4.1 Types

Mica Schists, Calc-Silicate Schists, Graphite Schists, Blueschists, Whiteschists, Greenschists, Hornblende Schist, Talc Schist, Chlorite Schist, Garnet Schist, Glaucophane schist.

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

4.2 Features

Easily splits into thin plates, Smooth to touch

Blocks negativity, Helps to protect against depression

4.3 Archaeological Significance

4.3.1 Monuments

Not Yet Used

4.3.2 Famous Monuments

Not Applicable

4.3.3 Sculpture

Not Yet Used

4.3.4 Famous Sculptures

Not Applicable

4.3.5 Pictographs

Used

4.3.6 Petroglyphs

Used

4.3.7 Figurines

Not Yet Used

4.4 Fossils

Absent

5 Formation

5.1 Formation

Schist formed by dynamic metamorphism at high temperatures and pressures that aligns the grains of mica, hornblende and other elongated minerals into thin layers.

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.

5.2 Composition

5.2.1 Mineral Content

Alusite, Amphibole, Biotite, Chlorite, Epidote, Feldspar, Garnet, Graphite, Hornblade, Kyanite, Micas, Muscovite or Illite, Porphyroblasts, Quartz, Sillimanite, Staurolite, Talc

Not Available

5.2.2 Compound Content

CaO, Carbon Dioxide, MgO

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

5.3 Transformation

5.3.1 Metamorphism

✔ ✘

5.3.2 Types of Metamorphism

Not Applicable

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism

5.3.3 Weathering

✔ ✘

5.3.4 Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

5.3.5 Erosion

✔ ✘

5.3.6 Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

6 Properties

6.1 Physical Properties

6.1.1 Hardness

3.5-45-5.5

1 7

6.1.2 Grain Size

Medium to Fine Coarse Grained

Not Applicable

6.1.3 Fracture

Conchoidal

6.1.4 Streak

White

6.1.5 Porosity

Highly Porous

Very Less Porous

6.1.6 Luster

Shiny

Vitreous

6.1.7 Compressive Strength

NA0.15 N/mm²

0.15 450

6.1.8 Cleavage

Slaty

Non-Existent

6.1.9 Toughness

1.5

Not Available

6.1.10 Specific Gravity

2.5-2.92.6-2.7

0 8.4

6.1.11 Transparency

Opaque

Translucent

6.1.12 Density

2.8-2.9 g/cm³2.6 g/cm³

0 1400

6.2 Thermal Properties

6.2.1 Specific Heat Capacity

NA0.92 kJ/Kg K

0.14 3.2

6.2.2 Resistance

Impact Resistant, Pressure Resistant, Water Resistant

Heat Resistant, Impact Resistant

7 Reserves

7.1 Deposits in Eastern Continents

7.1.1 Asia

Afghanistan, Bangladesh, Bhutan, China, India, Japan, Kazakhstan, Malaysia, Pakistan, Russia, Thailand, Turkey, Vietnam

Afghanistan, Indonesia, Japan, Russia

7.1.2 Africa

Egypt, Ethiopia, Morocco, Nigeria, South Africa

Kenya

7.1.3 Europe

Austria, England, France, Georgia, Germany, Italy, Liechtenstein, Monaco, Norway, Slovenia, Spain, Sweden, Switzerland

Greece, Hungary, Iceland, Italy, Turkey

7.1.4 Others

Not Yet Found

7.2 Deposits in Western Continents

7.2.1 North America

Canada, Costa Rica, Cuba, Mexico, Panama, USA

Canada, Mexico, USA

7.2.2 South America

Brazil, Colombia, Guyana

Argentina, Chile, Ecuador, Peru

7.3 Deposits in Oceania Continent

7.3.1 Australia

New South Wales, New Zealand, Queensland

New Zealand

All about Schist and Obsidian Properties

Know all about Schist and Obsidian properties here. All properties of rocks are important as they define the type of rock and its application. Schist belongs to Metamorphic Rocks while Obsidian belongs to Igneous Rocks.Texture of Schist is Foliated, Platy whereas that of Obsidian is Glassy. Schist appears Layered and Shiny and Obsidian appears Shiny. The luster of Schist is shiny while that of Obsidian is vitreous. Schist is available in black, blue, brown, dark brown, green, grey, silver colors whereas Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors. The commercial uses of Schist are used in aquariums, writing slates and that of Obsidian are creating artwork, mirror, used in aquariums.