Phyllite

Obsidian

Phyllite and Obsidian

Phyllite

Obsidian

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Definition

Phyllite is a fine-grained metamorphic rock with a well-developed laminar structure, and is intermediate between slate and schist rocks

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

Ethiopia

Discoverer

Unknown

Obsius

Etymology

From Greek phullon leaf + -ite1

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

Class

Metamorphic Rocks

Igneous Rocks

Sub-Class

Durable Rock, Soft Rock

Durable Rock, Medium Hardness Rock

Family

Group

Volcanic

Other Categories

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

Opaque Rock

Texture

Phyllitic Sheen, Slaty

Glassy

Color

Black to Grey, Light Greenish Grey

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

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Crinkled or Wavy

Shiny

Uses

Architecture

Interior Uses

Decorative Aggregates, Floor Tiles, Homes, Interior Decoration

Decorative Aggregates, Interior Decoration

Exterior Uses

As Building Stone, As Facing Stone, Garden Decoration

Garden Decoration

Other Architectural Uses

Curbing

Industry

Construction Industry

As Dimension Stone, Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate, Raw material for the manufacture of mortar, Roadstone

Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points

Medical Industry

Surgery

Antiquity Uses

Artifacts, Sculpture

Artifacts, Jewellery

Other Uses

Commercial Uses

Cemetery Markers, Commemorative Tablets, Creating Artwork, Writing Slates

Creating Artwork, Mirror, Used in aquariums

Types

Phyllite

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

Features

Easily splits into thin plates, Is one of the oldest rock, Surfaces are often shiny

Blocks negativity, Helps to protect against depression

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Formation

Phyllite is a metamorphic rock which is formed by regional metamorphism of argillaceous sediments since their cleavage arose due to deviatoric stress.

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

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

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

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, Water Erosion, Wind Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Properties

Physical Properties

Hardness

1-25-5.5

1 7

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Grain Size

Medium to Fine Coarse Grained

Fracture

Conchoidal

Streak

White

Porosity

Highly Porous

Very Less Porous

Luster

Phyllitic

Vitreous

Compressive Strength

50.00 N/mm²0.15 N/mm²

0.15 450

👆🏻

Cleavage

Crenulation and Pervasive

Toughness

1.2

Specific Gravity

2.72-2.732.6-2.7

0 8.4

👆🏻

Transparency

Opaque

Translucent

Density

2.18-3.3 g/cm³2.6 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.79 kJ/Kg K0.92 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Pressure Resistant, Water Resistant

Heat Resistant, Impact Resistant

Reserves

Deposits in Eastern Continents

Asia

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

Afghanistan, Indonesia, Japan, Russia

Africa

Egypt, Ethiopia, Morocco, Nigeria, South Africa

Kenya

Europe

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

Greece, Hungary, Iceland, Italy, Turkey

Others

Deposits in Western Continents

North America

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

Canada, Mexico, USA

South America

Brazil, Colombia, Guyana

Argentina, Chile, Ecuador, Peru

Deposits in Oceania Continent

Australia

New South Wales, New Zealand, Queensland

New Zealand

All about Phyllite and Obsidian Properties

Know all about Phyllite and Obsidian properties here. All properties of rocks are important as they define the type of rock and its application. Phyllite belongs to Metamorphic Rocks while Obsidian belongs to Igneous Rocks.Texture of Phyllite is Phyllitic Sheen, Slaty whereas that of Obsidian is Glassy. Phyllite appears Crinkled or Wavy and Obsidian appears Shiny. The luster of Phyllite is phyllitic while that of Obsidian is vitreous. Phyllite is available in black to grey, light greenish grey colors whereas Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors. The commercial uses of Phyllite are cemetery markers, commemorative tablets, creating artwork, writing slates and that of Obsidian are creating artwork, mirror, used in aquariums.