Slate

Obsidian

Slate and Obsidian

Slate

Obsidian

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Definition

Slate is a fine-grained, foliated, homogeneous metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade regional metamorphism

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

England

Ethiopia

Discoverer

Abraham Gottlob Werner

Obsius

Etymology

From Old French esclate, from esclat (French éclat)

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

Class

Metamorphic Rocks

Igneous Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Family

Group

Volcanic

Other Categories

Fine Grained Rock, Opaque Rock

Opaque Rock

Texture

Foliated

Glassy

Color

Black, Brown, Buff, Green, Light to Dark Grey, Purple, Red, Shades of Blue

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

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull

Shiny

Uses

Architecture

Interior Uses

Bathrooms, Decorative Aggregates, Entryways, Floor Tiles, Flooring, Homes, Hotels, Interior Decoration, Kitchens, Stair Treads

Decorative Aggregates, Interior Decoration

Exterior Uses

As Building Stone, As Facing Stone, Garden Decoration, Paving Stone

Garden Decoration

Other Architectural Uses

Curbing

Industry

Construction Industry

As Dimension Stone

Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points

Medical Industry

Surgery

Antiquity Uses

Artifacts, Monuments, Sculpture, Small Figurines

Artifacts, Jewellery

Other Uses

Commercial Uses

Blackboards, Commemorative Tablets, Laboratory bench tops, Standard material for the bed of Billiard table, Standard material for the beds of Pool and Snooker table, Tombstones, Used in aquariums, Writing Slates

Creating Artwork, Mirror, Used in aquariums

Types

Phyllite, Schist, and Slate

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

Features

Easily splits into thin plates, Surfaces are often shiny, Very fine grained rock

Blocks negativity, Helps to protect against depression

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Formation

Slate is a low grade metamorphic rock that is generally formed by metamorphosis of mudstone or shale, under relatively low pressure and temperature conditions.

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

Apatite, Biotite, Chlorite, Feldspar, Graphite, Hematite, Kaolinite, Magnetite, Pyrite, Tourmaline, Zircon

Compound Content

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

3-45-5.5

1 7

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Grain Size

Very fine-grained

Fracture

Splintery

Conchoidal

Streak

Light to dark brown

White

Porosity

Less Porous

Very Less Porous

Luster

Dull

Vitreous

Compressive Strength

30.00 N/mm²0.15 N/mm²

0.15 450

👆🏻

Cleavage

Slaty

Toughness

1.2

Specific Gravity

2.65-2.82.6-2.7

0 8.4

👆🏻

Transparency

Opaque

Translucent

Density

2.6-2.8 g/cm³2.6 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.76 kJ/Kg K0.92 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Heat Resistant, Impact Resistant

Reserves

Deposits in Eastern Continents

Asia

China, India, Turkey

Afghanistan, Indonesia, Japan, Russia

Africa

Kenya

Europe

Belgium, France, Germany, Italy, Norway, Portugal, Spain, United Kingdom

Greece, Hungary, Iceland, Italy, Turkey

Others

Arctic

Deposits in Western Continents

North America

USA

Canada, Mexico, USA

South America

Brazil

Argentina, Chile, Ecuador, Peru

Deposits in Oceania Continent

Australia

New Zealand

All about Slate and Obsidian Properties

Know all about Slate and Obsidian properties here. All properties of rocks are important as they define the type of rock and its application. Slate belongs to Metamorphic Rocks while Obsidian belongs to Igneous Rocks.Texture of Slate is Foliated whereas that of Obsidian is Glassy. Slate appears Dull and Obsidian appears Shiny. The luster of Slate is dull while that of Obsidian is vitreous. Slate is available in black, brown, buff, green, light to dark grey, purple, red, shades of blue colors whereas Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors. The commercial uses of Slate are blackboards, commemorative tablets, laboratory bench tops, standard material for the bed of billiard table, standard material for the beds of pool and snooker table, tombstones, used in aquariums, writing slates and that of Obsidian are creating artwork, mirror, used in aquariums.