Porphyry

Banded iron formation

Porphyry vs Banded iron formation

Porphyry

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Definition

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

Banded iron formation are distinctive units of sedimentary rock that are almost always of Precambrian age

History

Origin

Egypt

Western Australia, Minnesota

Discoverer

Unknown

Johann Gottlob Lehmann

Etymology

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

From its formation process

Class

Igneous Rocks

Sedimentary Rocks

Sub-Class

Durable Rock, Hard Rock

Durable Rock, Medium Hardness Rock

Family

Group

Plutonic

Other Categories

Fine Grained Rock, Opaque Rock

Coarse Grained Rock, Opaque Rock

Texture

Porphyritic

Banded, Trellis

Color

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

Red, Reddish Brown

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull

Layered, Banded, Veined and Shiny

Uses

Architecture

Interior Uses

Decorative Aggregates, Interior Decoration

Decorative Aggregates, Homes

Exterior Uses

Garden Decoration, Paving Stone

Paving Stone, Office Buildings

Other Architectural Uses

Curbing

Curbing, Whetstones

Industry

Construction Industry

Construction Aggregate

As Dimension Stone, Used for flooring, stair treads, borders and window sills.

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture

Artifacts

Other Uses

Commercial Uses

Creating Artwork, Gemstone, Jewelry

As a touchstone, Cemetery Markers, Creating Artwork

Types

Rhomb Porphyry

Algoma-type , Lake Superior-type, Superior-type and Taconite

Features

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

Is one of the oldest rock

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Present

Formation

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.

The banded iron layers are formed in sea water when oxygen is released by photosynthetic cyano-bacteria. The oxygen then combines with dissolved iron in ocean to form insoluble iron oxides, which precipitated out, forming a thin layer of banded iron formation on ocean floor.

Composition

Mineral Content

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

Hematite, Magnetite, Quartz

Compound Content

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

Fe, Iron(III) Oxide, Silicon 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

Chemical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Coastal Erosion, Wind Erosion

Properties

Physical Properties

Hardness

6-75.5-6

1 7

👆🏻

Grain Size

Fine Grained

Large and Coarse Grained

Fracture

Irregular

Uneven, Splintery or Conchoidal

Streak

White

Porosity

Less Porous

Highly Porous

Luster

Dull

Earthy

Compressive Strength

150.00 N/mm²220.00 N/mm²

0.15 450

👆🏻

Cleavage

Toughness

1.7

1.5

Specific Gravity

2.5-45.0-5.3

0 8.4

👆🏻

Transparency

Translucent to Opaque

Density

2.5-2.52 g/cm³-9999 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.71 kJ/Kg K3.20 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

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

China, India, Iran, Iraq, Oman, Russia, Saudi Arabia, Taiwan, Thailand, Vietnam

Africa

Egypt, Ethiopia, Ghana, South Africa

Kenya, Morocco, South Africa, Tanzania

Europe

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

Austria, France, Greece, Italy, Malta, Poland, Portugal, Serbia, Spain, Sweden, United Kingdom

Others

Greenland

Greenland, Mid-Atlantic Ridge

Deposits in Western Continents

North America

Canada, Cuba, Jamaica, USA

Canada, Mexico, USA

South America

Bolivia, Brazil, Colombia, Ecuador, Paraguay

Bolivia, Brazil

Deposits in Oceania Continent

Australia

New South Wales, New Zealand, Western Australia

New South Wales, Queensland, South Australia, Western Australia

Porphyry vs Banded iron formation 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 Porphyry and Banded iron formation Reserves. Porphyry is a reddish-brown to purple igneous rock containing large phenocrysts of various minerals embedded in a fine-grained matrix. Banded iron formation are distinctive units of sedimentary rock that are almost always of Precambrian age. 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 Porphyry vs Banded iron formation information and Porphyry vs Banded iron formation characteristics in the upcoming sections.

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Porphyry vs Banded iron formation 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. Porphyry vs Banded iron formation characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Porphyry and Properties of Banded iron formation. Learn more about Porphyry vs Banded iron formation in the next section. The interior uses of Porphyry include Decorative aggregates and Interior decoration whereas the interior uses of Banded iron formation include Decorative aggregates and Homes. Due to some exceptional properties of Porphyry and Banded iron formation, they have various applications in construction industry. The uses of Porphyry in construction industry include Construction aggregate and that of Banded iron formation include As dimension stone, Used for flooring, stair treads, borders and window sills..

More about Porphyry and Banded iron formation

Here you can know more about Porphyry and Banded iron formation. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Porphyry and Banded iron formation consists of mineral content and compound content. The mineral content of Porphyry includes Biotite, Chert, Feldspar, Garnet, Graphite, Quartz, Silica and mineral content of Banded iron formation includes Hematite, Magnetite, Quartz. You can also check out the list of all Igneous Rocks. When we have to compare Porphyry vs Banded iron formation, the texture, color and appearance plays an important role in determining the type of rock. Porphyry is available in black, brown, green, grey, red, rust, white colors whereas, Banded iron formation is available in red, reddish brown colors. Appearance of Porphyry is Dull and that of Banded iron formation is Layered, Banded, Veined and Shiny. Properties of rock is another aspect for Porphyry vs Banded iron formation. The hardness of Porphyry is 6-7 and that of Banded iron formation is 5.5-6. The types of Porphyry are Rhomb Porphyry whereas types of Banded iron formation are Algoma-type , Lake Superior-type, Superior-type and Taconite. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Porphyry and Banded iron formation is white. The specific heat capacity of Porphyry is 0.71 kJ/Kg K and that of Banded iron formation is 3.20 kJ/Kg K. Depending on the properties like hardness, toughness, specific heat capacity, porosity etc., rocks are resistant to heat, wear, impact, etc.Porphyry is heat resistant, impact resistant whereas Banded iron formation is heat resistant, impact resistant, pressure resistant, wear resistant.