Skarn

Porphyry

Skarn and Porphyry

Skarn

Porphyry

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Definition

Skarns are formed during regional or contact metamorphism and from a variety of metasomatic processes involving fluids of magmatic, metamorphic, and/or marine origin

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

History

Origin

USA, Australia

Egypt

Discoverer

Tornebohm

Unknown

Etymology

From an old Swedish mining term originally used to describe a type of silicate gangue or waste rock.

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

Class

Metamorphic Rocks

Igneous Rocks

Sub-Class

Durable Rock, Hard Rock

Family

Group

Plutonic

Other Categories

Fine Grained Rock, Opaque Rock

Texture

Earthy, Mud-rich, Rough

Porphyritic

Color

Black, Brown, Green, Grey, White

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

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull

Uses

Architecture

Interior Uses

Decorative Aggregates, Entryways, Interior Decoration

Decorative Aggregates, Interior Decoration

Exterior Uses

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

Garden Decoration, Paving Stone

Other Architectural Uses

Curbing

Industry

Construction Industry

As a Flux in the Production of Steel and Pig Iron, As a Sintering Agent in Steel Industry to process Iron Ore, As Dimension Stone, Gold and Silver production, Manufacture of Magnesium and Dolomite Refractories

Construction Aggregate

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture

Other Uses

Commercial Uses

Creating Artwork, Gemstone, Jewelry, Metallurgical Flux, Source of Magnesia (MgO)

Creating Artwork, Gemstone, Jewelry

Types

Endoskarns

Rhomb Porphyry

Features

Host Rock for Lead, Zinc and Copper Deposits

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

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Formation

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

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

Calcite, Enstatite, Epidote, Garnet, Magnetite, Pyroxene, Titanite

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

Compound Content

Au, CaO, Carbon Dioxide, Cu, Fe, MgO

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

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Properties

Physical Properties

Hardness

6.56-7

1 7

👆🏻

Grain Size

Fine Grained

Fracture

Irregular

Streak

Light to dark brown

White

Porosity

Less Porous

Luster

Waxy and Dull

Dull

Compressive Strength

70.00 N/mm²150.00 N/mm²

0.15 450

👆🏻

Cleavage

Slaty

Toughness

2.4

1.7

Specific Gravity

2.862.5-4

0 8.4

👆🏻

Transparency

Opaque

Translucent to Opaque

Density

2.8-2.9 g/cm³2.5-2.52 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.92 kJ/Kg K0.71 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant

Heat Resistant, Impact Resistant

Reserves

Deposits in Eastern Continents

Asia

China, India, Russia, Saudi Arabia, South Korea, Sri Lanka

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

Africa

South Africa, Western Africa

Egypt, Ethiopia, Ghana, South Africa

Europe

United Kingdom

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

Others

Greenland

Deposits in Western Continents

North America

Canada

Canada, Cuba, Jamaica, USA

South America

Brazil, Colombia, Paraguay

Bolivia, Brazil, Colombia, Ecuador, Paraguay

Deposits in Oceania Continent

Australia

Central Australia, Western Australia

New South Wales, New Zealand, Western Australia

All about Skarn and Porphyry Properties

Know all about Skarn and Porphyry properties here. All properties of rocks are important as they define the type of rock and its application. Skarn belongs to Metamorphic Rocks while Porphyry belongs to Igneous Rocks.Texture of Skarn is Earthy, Mud-rich, Rough whereas that of Porphyry is Porphyritic. Skarn appears Dull and Porphyry appears Dull. The luster of Skarn is waxy and dull while that of Porphyry is dull. Skarn is available in black, brown, green, grey, white colors whereas Porphyry is available in black, brown, green, grey, red, rust, white colors. The commercial uses of Skarn and Porphyry are creating artwork, gemstone, jewelry, metallurgical flux, source of magnesia (mgo).