Schist

Comendite

Schist and Comendite

Schist

Comendite

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Definition

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

Comendite is a hard, peralkaline igneous rock, a type of light blue grey rhyolite

History

Origin

Italy

Discoverer

Unknown

Etymology

From French schiste, Greek skhistos i.e. split

Comendite derives its name from the area of Le Commende on San Pietro Island in Italy

Class

Metamorphic Rocks

Igneous Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Durable Rock, Hard Rock

Family

Group

Volcanic

Other Categories

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

Medium Grained Rock, Opaque Rock

Texture

Foliated, Platy

Porphyritic

Color

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

Blue, Bluish - Grey

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Layered and Shiny

Foliated

Uses

Architecture

Interior Uses

Decorative Aggregates, Floor Tiles, Interior Decoration

Countertops, Decorative Aggregates, Interior Decoration

Exterior Uses

Garden Decoration, Paving Stone

As Building Stone, As Facing Stone, Garden Decoration

Other Architectural Uses

Curbing

Industry

Construction Industry

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

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

Medical Industry

Antiquity Uses

Artifacts

Other Uses

Commercial Uses

Used in aquariums, Writing Slates

Cemetery Markers

Types

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

Rhyolite

Features

Easily splits into thin plates, Smooth to touch

Very fine grained rock, It is One of the Oldest, Strongest and Hardest Rock

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

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.

Comendite is a type of Igneous rock which is formed due to cooling and solidification of lava or magma. It may form with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.

Composition

Mineral Content

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

Albite, Amphibole, Quartz

Compound Content

CaO, Carbon Dioxide, MgO

Al, Fe, Potassium Oxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Cataclastic Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Coastal Erosion, Water Erosion

Properties

Physical Properties

Hardness

3.5-46-7

1 7

👆🏻

Grain Size

Medium to Fine Coarse Grained

Medium Grained

Fracture

Conchoidal

Pervasive

Streak

White

Bluish Black

Porosity

Highly Porous

Luster

Shiny

Dull

Compressive Strength

150.00 N/mm²92.40 N/mm²

0.15 450

👆🏻

Cleavage

Slaty

Toughness

1.5

Specific Gravity

2.5-2.92.38

0 8.4

👆🏻

Transparency

Opaque

Density

2.8-2.9 g/cm³-9999 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.70 kJ/Kg K0.79 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Impact 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

China

Africa

Egypt, Ethiopia, Morocco, Nigeria, South Africa

East Africa

Europe

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

Italy

Others

Deposits in Western Continents

North America

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

South America

Brazil, Colombia, Guyana

Deposits in Oceania Continent

Australia

New South Wales, New Zealand, Queensland

Queensland

All about Schist and Comendite Properties

Know all about Schist and Comendite properties here. All properties of rocks are important as they define the type of rock and its application. Schist belongs to Metamorphic Rocks while Comendite belongs to Igneous Rocks.Texture of Schist is Foliated, Platy whereas that of Comendite is Porphyritic. Schist appears Layered and Shiny and Comendite appears Foliated. The luster of Schist is shiny while that of Comendite is dull. Schist is available in black, blue, brown, dark brown, green, grey, silver colors whereas Comendite is available in blue, bluish - grey colors. The commercial uses of Schist are used in aquariums, writing slates and that of Comendite are cemetery markers.