Shale

Porphyry

Shale vs Porphyry

Shale

Porphyry

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Definition

Shale is a fine-grained sedimentary rock which is formed by the compaction of silt and clay-size mineral particles

Porphyry is a reddish-brown to purple igneous rock containing large phenocrysts of various minerals embedded in a fine-grained matrix

History

Origin

Egypt

Discoverer

Johann Gottlob Lehmann

Unknown

Etymology

From German Schalstein laminated limestone, and Schalgebirge layer of stone in stratified rock. From Old English scealu in its base sense of- thing that divides or separate,

From Old French porfire, from Italian porfiro and in some cases directly from Latin porphyrites

Class

Sedimentary Rocks

Igneous Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Durable Rock, Hard Rock

Family

Group

Plutonic

Other Categories

Fine Grained Rock, Opaque Rock

Texture

Clastic, Splintery

Porphyritic

Color

Black, Brown, Buff, Green, Grey, Red, Yellow

Black, Brown, Green, Grey, Red, Rust, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Muddy

Dull

Uses

Architecture

Interior Uses

Decorative Aggregates, Homes, Interior Decoration

Decorative Aggregates, Interior Decoration

Exterior Uses

As Building Stone, As Facing Stone, Office Buildings

Garden Decoration, Paving Stone

Other Architectural Uses

Curbing

Industry

Construction Industry

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

Construction Aggregate

Medical Industry

Antiquity Uses

Artifacts, Sculpture

Artifacts, Monuments, Sculpture

Other Uses

Commercial Uses

Creating Artwork, Pottery

Creating Artwork, Gemstone, Jewelry

Types

Red Shale, Black Shale, Green Shale, Grey Shale and Yellow Shale

Rhomb Porphyry

Features

Easily splits into thin plates, Generally rough to touch, Very fine grained rock

Generally rough to touch, Is one of the oldest rock, Surfaces are often shiny

Archaeological Significance

Monuments

Famous Monuments

Jantar Mantar in India

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Present

Absent

Formation

Shale forms when very fine-grained clay particles are deposited in water which settle at the bottom of water bodies. They are later compacted hence forming shale.

Porphyry is formed in two stages: the magma cools slowly deep within the crust or the magma is cools rapidly as it erupts from a volcano, creating small grains that are usually invisible to naked eye.

Composition

Mineral Content

Albite, Biotite, Calcite, Chert, Chlorite, Dolomite, Hematite, Micas, Muscovite or Illite, Pyrite, Quartz, Silica, Sulfides

Biotite, Chert, Feldspar, Garnet, Graphite, Quartz, Silica

Compound Content

Ca, Fe, Mg, Silicon Dioxide, Sodium

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

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Biological Weathering, Chemical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Properties

Physical Properties

Hardness

36-7

1 7

👆🏻

Grain Size

Very fine-grained

Fine Grained

Fracture

Irregular

Streak

White

Porosity

Highly Porous

Less Porous

Luster

Dull

Compressive Strength

95.00 N/mm²150.00 N/mm²

0.15 450

👆🏻

Cleavage

Slaty

Toughness

2.6

1.7

Specific Gravity

2.2-2.82.5-4

0 8.4

👆🏻

Transparency

Opaque

Translucent to Opaque

Density

2.4-2.8 g/cm³2.5-2.52 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.39 kJ/Kg K0.71 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant

Reserves

Deposits in Eastern Continents

Asia

Bangladesh, China, India, Russia

China, Kazakhstan, South Korea, Thailand, Turkey, Vietnam

Africa

Ethiopia, Kenya, Morocco, South Africa, Tanzania

Egypt, Ethiopia, Ghana, South Africa

Europe

Austria, France, Germany, Greece, Italy, Romania, Scotland, Spain, Switzerland

Finland, France, Germany, Great Britain, Hungary, Iceland, Ireland, Italy, Netherlands, Norway, Romania, Sweden, Switzerland

Others

Greenland

Deposits in Western Continents

North America

USA

Canada, Cuba, Jamaica, USA

South America

Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela

Bolivia, Brazil, Colombia, Ecuador, Paraguay

Deposits in Oceania Continent

Australia

New South Wales, New Zealand, Queensland, Victoria, Western Australia

New South Wales, New Zealand, Western Australia

Shale vs Porphyry Information

Earth’s outer layer is covered by rocks and these rocks have different physical and chemical properties. As two rocks are not same, it’s fun to compare them. You can also know more about Shale and Porphyry Reserves. Shale is a fine-grained sedimentary rock which is formed by the compaction of silt and clay-size mineral particles. Porphyry is a reddish-brown to purple igneous rock containing large phenocrysts of various minerals embedded in a fine-grained matrix. These rocks are composed of many distinct minerals. The process of formation of rocks is different for various rocks. Rocks are quarried from many years for various purposes. You can check out Shale vs Porphyry information and Shale vs Porphyry characteristics in the upcoming sections.

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Shale vs Porphyry Characteristics

Though some rocks look identical, they have certain characteristics which distinguish them from others. Characteristics of rocks include texture, appearance, color, fracture, streak, hardness etc. Shale vs Porphyry characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Shale and Properties of Porphyry. Learn more about Shale vs Porphyry in the next section. The interior uses of Shale include Decorative aggregates, Homes and Interior decoration whereas the interior uses of Porphyry include Decorative aggregates and Interior decoration. Due to some exceptional properties of Shale and Porphyry, they have various applications in construction industry. The uses of Shale in construction industry include Cement manufacture, Construction aggregate, For road aggregate, Making natural cement, Raw material for the manufacture of mortar and that of Porphyry include Construction aggregate.

More about Shale and Porphyry

Here you can know more about Shale and Porphyry. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Shale and Porphyry consists of mineral content and compound content. The mineral content of Shale includes Albite, Biotite, Calcite, Chert, Chlorite, Dolomite, Hematite, Micas, Muscovite or Illite, Pyrite, Quartz, Silica, Sulfides and mineral content of Porphyry includes Biotite, Chert, Feldspar, Garnet, Graphite, Quartz, Silica. You can also check out the list of all Sedimentary Rocks. When we have to compare Shale vs Porphyry, the texture, color and appearance plays an important role in determining the type of rock. Shale is available in black, brown, buff, green, grey, red, yellow colors whereas, Porphyry is available in black, brown, green, grey, red, rust, white colors. Appearance of Shale is Muddy and that of Porphyry is Dull. Properties of rock is another aspect for Shale vs Porphyry. The hardness of Shale is 3 and that of Porphyry is 6-7. The types of Shale are Red Shale, Black Shale, Green Shale, Grey Shale and Yellow Shale whereas types of Porphyry are Rhomb Porphyry. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Shale and Porphyry is white. The specific heat capacity of Shale is 0.39 kJ/Kg K and that of Porphyry is 0.71 kJ/Kg K. Depending on the properties like hardness, toughness, specific heat capacity, porosity etc., rocks are resistant to heat, wear, impact, etc.Shale is heat resistant, impact resistant whereas Porphyry is heat resistant, impact resistant.