Porphyry

Hornfels

Porphyry vs Hornfels

Porphyry

Hornfels

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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

Hornfels is a metamorphic rock formed by the contact between mudstone or other clay rich rock, and a hot igneous body, and represents a heat altered equivalent of the original rock

History

Origin

Egypt

New Zealand

Discoverer

Unknown

Etymology

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

From German which means hornstone

Class

Igneous Rocks

Metamorphic Rocks

Sub-Class

Durable Rock, Hard Rock

Durable Rock, Soft Rock

Family

Group

Plutonic

Other Categories

Fine Grained Rock, Opaque Rock

Texture

Porphyritic

Granular, Platy

Color

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

Brown, Dark Greenish - Grey, Green, Reddish Brown

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull

Uses

Architecture

Interior Uses

Decorative Aggregates, Interior Decoration

Decorative Aggregates, Flooring, Homes, Interior Decoration

Exterior Uses

Garden Decoration, Paving Stone

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

Other Architectural Uses

Curbing

Industry

Construction Industry

Construction Aggregate

for Road Aggregate, Roadstone

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture

Artifacts, Monuments

Other Uses

Commercial Uses

Creating Artwork, Gemstone, Jewelry

Cemetery Markers, Commemorative Tablets, Creating Artwork

Types

Rhomb Porphyry

Biotite hornfels

Features

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

Smooth to touch

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

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.

Due to change in environmental conditions, rocks are heated and pressurized deep inside the Earth's surface. Hornfels is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.

Composition

Mineral Content

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

Andalusite

Compound Content

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

Fe, Mg

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

Biological Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Chemical Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion

Properties

Physical Properties

Hardness

6-72-3

1 7

👆🏻

Grain Size

Fine Grained

Fracture

Irregular

Conchoidal

Streak

White

Porosity

Less Porous

Highly Porous

Luster

Dull

Shiny

Compressive Strength

150.00 N/mm²5.80 N/mm²

0.15 450

👆🏻

Cleavage

Perfect

Toughness

1.7

Specific Gravity

2.5-43.4-3.9

0 8.4

👆🏻

Transparency

Translucent to Opaque

Opaque

Density

2.5-2.52 g/cm³0.25-0.30 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.71 kJ/Kg K0.84 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant

Heat Resistant, Impact Resistant, Pressure Resistant

Reserves

Deposits in Eastern Continents

Asia

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

Bangladesh, Bhutan, China, India, North Korea, Qatar, Russia, Saudi Arabia, South Korea, Thailand

Africa

Egypt, Ethiopia, Ghana, South Africa

Cameroon, East Africa, Tanzania, Western Africa

Europe

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

United Kingdom

Others

Greenland

Deposits in Western Continents

North America

Canada, Cuba, Jamaica, USA

Canada, USA

South America

Bolivia, Brazil, Colombia, Ecuador, Paraguay

Bolivia, Brazil, Colombia, Ecuador

Deposits in Oceania Continent

Australia

New South Wales, New Zealand, Western Australia

New South Wales, New Zealand, Queensland, Western Australia

Porphyry vs Hornfels 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 Hornfels Reserves. Porphyry is a reddish-brown to purple igneous rock containing large phenocrysts of various minerals embedded in a fine-grained matrix. Hornfels is a metamorphic rock formed by the contact between mudstone or other clay rich rock, and a hot igneous body, and represents a heat altered equivalent of the original rock. 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 Hornfels information and Porphyry vs Hornfels characteristics in the upcoming sections.

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Porphyry vs Hornfels 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 Hornfels characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Porphyry and Properties of Hornfels. Learn more about Porphyry vs Hornfels in the next section. The interior uses of Porphyry include Decorative aggregates and Interior decoration whereas the interior uses of Hornfels include Decorative aggregates, Flooring, Homes and Interior decoration. Due to some exceptional properties of Porphyry and Hornfels, they have various applications in construction industry. The uses of Porphyry in construction industry include Construction aggregate and that of Hornfels include For road aggregate, Roadstone.

More about Porphyry and Hornfels

Here you can know more about Porphyry and Hornfels. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Porphyry and Hornfels consists of mineral content and compound content. The mineral content of Porphyry includes Biotite, Chert, Feldspar, Garnet, Graphite, Quartz, Silica and mineral content of Hornfels includes Andalusite. You can also check out the list of all Igneous Rocks. When we have to compare Porphyry vs Hornfels, 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, Hornfels is available in brown, dark greenish - grey, green, reddish brown colors. Appearance of Porphyry is Dull and that of Hornfels is Dull. Properties of rock is another aspect for Porphyry vs Hornfels. The hardness of Porphyry is 6-7 and that of Hornfels is 2-3. The types of Porphyry are Rhomb Porphyry whereas types of Hornfels are Biotite hornfels. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Porphyry is white while that of Hornfels is . The specific heat capacity of Porphyry is 0.71 kJ/Kg K and that of Hornfels is 0.84 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 Hornfels is heat resistant, impact resistant, pressure resistant.