Porphyry

Migmatite

Porphyry and Migmatite

Porphyry

Migmatite

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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

Migmatite is typically a granitic rock within a metamorphic host rock which is composed of two intermingled but distinguishable components

History

Origin

Egypt

Southern Alps, France

Discoverer

Unknown

Jakob Sederholm

Etymology

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

From the Greek word migma which means a mixture

Class

Igneous Rocks

Metamorphic 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, Fine Grained Rock, Medium Grained Rock, Opaque Rock

Texture

Porphyritic

Foliated

Color

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

Black, Bluish - Grey, Brown, Brown- Black, Dark Greenish - Grey, Dark Grey to Black

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull

Dull, Banded and Foilated

Uses

Architecture

Interior Uses

Decorative Aggregates, Interior Decoration

Countertops, Flooring, Kitchens

Exterior Uses

Garden Decoration, Paving Stone

As Building Stone, As Facing Stone

Other Architectural Uses

Curbing

Industry

Construction Industry

Construction Aggregate

As Dimension Stone, Cement Manufacture, for Road Aggregate, Making natural cement

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture

Artifacts

Other Uses

Commercial Uses

Creating Artwork, Gemstone, Jewelry

Cemetery Markers, Jewelry, Tombstones, Used to manufracture paperweights and bookends

Types

Rhomb Porphyry

Diatexites and Metatexites

Features

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

Generally rough to touch, Is one of the oldest rock

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.

Migmatites form by high temperature regional and thermal metamorphism of protolith rocks where rocks melt partially due to high temperature.

Composition

Mineral Content

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

Biotite, Chlorite, Feldspar, Garnet, Graphite, Hornblade, Micas, Muscovite or Illite, Quartz, Quartzite, Silica, Zircon

Compound Content

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

Aluminium Oxide, NaCl, CaO, Carbon Dioxide, Iron(III) Oxide, FeO, Potassium Oxide, Magnesium Carbonate, MgO, MnO, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

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

Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Chemical Erosion, Glacier Erosion, Water Erosion, Wind Erosion

Properties

Physical Properties

Hardness

6-75.5-6.5

1 7

👆🏻

Grain Size

Fine Grained

Medium to Fine Coarse Grained

Fracture

Irregular

Streak

White

Porosity

Less Porous

Very Less Porous

Luster

Dull

Dull to Pearly to Subvitreous

Compressive Strength

150.00 N/mm²120.00 N/mm²

0.15 450

👆🏻

Cleavage

Toughness

1.7

1.2

Specific Gravity

2.5-42.65-2.75

0 8.4

👆🏻

Transparency

Translucent to Opaque

Opaque

Density

2.5-2.52 g/cm³-9999 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.71 kJ/Kg K0.79 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant

Heat Resistant, Pressure Resistant

Reserves

Deposits in Eastern Continents

Asia

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

China, India, Iran, Iraq, Kazakhstan, Kyrgyzstan, Mongolia, Russia

Africa

Egypt, Ethiopia, Ghana, South Africa

Cameroon, Ethiopia, Ghana, Kenya, Madagascar, Morocco, Mozambique, Namibia, Nigeria, Tanzania, Togo

Europe

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

Albania, Austria, Bosnia and Herzegovina, Finland, France, Georgia, Germany, Hungary, Italy, Kosovo, Monaco, Norway, Poland, Romania, Serbia, Slovakia, Slovenia, Sweden, Switzerland, Ukraine, United Kingdom

Others

Greenland

Deposits in Western Continents

North America

Canada, Cuba, Jamaica, USA

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

South America

Bolivia, Brazil, Colombia, Ecuador, Paraguay

Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Peru, Venezuela

Deposits in Oceania Continent

Australia

New South Wales, New Zealand, Western Australia

New South Wales, New Zealand, Queensland, Victoria

All about Porphyry and Migmatite Properties

Know all about Porphyry and Migmatite properties here. All properties of rocks are important as they define the type of rock and its application. Porphyry belongs to Igneous Rocks while Migmatite belongs to Metamorphic Rocks.Texture of Porphyry is Porphyritic whereas that of Migmatite is Foliated. Porphyry appears Dull and Migmatite appears Dull, Banded and Foilated. The luster of Porphyry is dull while that of Migmatite is dull to pearly to subvitreous. Porphyry is available in black, brown, green, grey, red, rust, white colors whereas Migmatite is available in black, bluish - grey, brown, brown- black, dark greenish - grey, dark grey to black colors. The commercial uses of Porphyry are creating artwork, gemstone, jewelry and that of Migmatite are cemetery markers, jewelry, tombstones, used to manufracture paperweights and bookends.