Porphyry

Gabbro

Porphyry and Gabbro

Porphyry

Gabbro

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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

Gabbro is an intrusive igneous rock which is chemically equivalent to plutonic Basalt

History

Origin

Egypt

Germany

Discoverer

Unknown

Christian Leopold von Buch

Etymology

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

From Latin glaber bare, smooth, bald

Class

Igneous Rocks

Sub-Class

Durable Rock, Hard Rock

Family

Group

Plutonic

Other Categories

Fine Grained Rock, Opaque Rock

Coarse Grained Rock, Opaque Rock

Texture

Porphyritic

Phaneritic

Color

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

Dark Grey to Black

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull

Veined and Shiny

Uses

Architecture

Interior Uses

Decorative Aggregates, Interior Decoration

Countertops, Decorative Aggregates, 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

As Dimension Stone, Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture

Other Uses

Commercial Uses

Creating Artwork, Gemstone, Jewelry

Cemetery Markers, Commemorative Tablets, Laboratory bench tops, Jewelry, Sea Defence, Tombstones

Types

Rhomb Porphyry

Anorthosite Gabbro and Norite Gabbro

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.

Gabbro, a mafic rock, forms due to cooling and crystallization of magma underneath Earth's surface.

Composition

Mineral Content

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

Augite, Olivine, Plagioclase, Pyroxene

Compound Content

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

Aluminium Oxide, CaO, Chromium(III) Oxide, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Sulfur Trioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

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

Impact Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering

Chemical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Coastal Erosion

Properties

Physical Properties

Hardness

6-77

1 7

👆🏻

Grain Size

Fine Grained

Coarse Grained

Fracture

Irregular

Conchoidal

Streak

White

Black

Porosity

Less Porous

Highly Porous

Luster

Dull

Compressive Strength

150.00 N/mm²225.00 N/mm²

0.15 450

👆🏻

Cleavage

Toughness

1.7

1.6

Specific Gravity

2.5-42.86-2.87

0 8.4

👆🏻

Transparency

Translucent to Opaque

Opaque

Density

2.5-2.52 g/cm³2.7-3.3 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.71 kJ/Kg K0.71 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant

Impact Resistant, Pressure Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

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

India, Russia

Africa

Egypt, Ethiopia, Ghana, South Africa

South Africa

Europe

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

Germany, Greece, Italy, Scotland, Turkey

Others

Greenland

Deposits in Western Continents

North America

Canada, Cuba, Jamaica, USA

Canada, USA

South America

Bolivia, Brazil, Colombia, Ecuador, Paraguay

Brazil, Colombia, Venezuela

Deposits in Oceania Continent

Australia

New South Wales, New Zealand, Western Australia

New Zealand, Queensland

All about Porphyry and Gabbro Properties

Know all about Porphyry and Gabbro properties here. All properties of rocks are important as they define the type of rock and its application. Porphyry and Gabbro belong to Igneous Rocks.Texture of Porphyry is Porphyritic whereas that of Gabbro is Phaneritic. Porphyry appears Dull and Gabbro appears Veined and Shiny. The luster of Porphyry is dull while that of Gabbro is . Porphyry is available in black, brown, green, grey, red, rust, white colors whereas Gabbro is available in dark grey to black colors. The commercial uses of Porphyry are creating artwork, gemstone, jewelry and that of Gabbro are cemetery markers, commemorative tablets, laboratory bench tops, jewelry, sea defence, tombstones.