Porphyry and Andesite

Porphyry

Andesite

Definition

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

Andesite is a dark, fine-grained, brown or greyish intermediate volcanic rock which is a commonly found in lava

History

Origin

Egypt

North America

Discoverer

Unknown

Etymology

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

From Andes mountains, where it is found in abundance

Class

Igneous Rocks

Sub-Class

Durable Rock, Hard Rock

Family

Group

Plutonic

Volcanic

Other Categories

Fine Grained Rock, Opaque Rock

Texture

Porphyritic

Aphanitic to Porphyritic

Color

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

Bluish - Grey, Grey, Pink, Yellow

Maintenance

Less

Durability

Durable

Water Resistant

Scratch Resistant

Yes

Stain Resistant

Yes

Wind Resistant

Acid Resistant

Yes

Appearance

Dull

Dull and Soft

Uses

Architecture

Interior Uses

Decorative Aggregates, Interior Decoration

Decorative Aggregates, Floor Tiles, Homes, Interior Decoration, Kitchens

Exterior Uses

Garden Decoration, Paving Stone

Office Buildings, Roof Tiles

Other Architectural Uses

Curbing

Industry

Construction Industry

Construction Aggregate

Cobblestones, Construction Aggregate, for Road Aggregate

Medical Industry

Not Yet Used

Antiquity Uses

Artifacts, Monuments, Sculpture

Artifacts, Monuments, Sculpture, Small Figurines

Other Uses

Commercial Uses

Creating Artwork, Gemstone, Jewelry

Commemorative Tablets, Creating Artwork

Types

Rhomb Porphyry

Icelandite

Features

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

Generally rough to touch, High silica content, Is one of the oldest rock

Archaeological Significance

Monuments

Used

Famous Monuments

Data Not Available

Middle of the Earth in Ecuador

Sculpture

Used

Famous Sculptures

Data Not Available

Pictographs

Not Used

Petroglyphs

Not Used

Figurines

Used

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.

Andesite is a fine-grained igneous rock that forms when the magma is erupted onto the surface and is crystallized quickly.

Composition

Mineral Content

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

Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Ilmenite, Magnetite, Plagioclase, Pyroxene, Zircon

Compound Content

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

Silicon Dioxide

Transformation

Metamorphism

Yes

Types of Metamorphism

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

Weathering

Yes

Types of Weathering

Biological Weathering, Chemical Weathering, Not Registered

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

Yes

Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Properties

Physical Properties

Hardness

6-7

Grain Size

Fine Grained

Very fine-grained

Fracture

Irregular

Uneven

Streak

White

Porosity

Less Porous

Luster

Dull

Vitreous

Compressive Strength

Not Available

225.00 N/mm²

Cleavage

Imperfect

Not Available

Toughness

1.7

1.1

Specific Gravity

2.5-4

2.5-2.8

Transparency

Translucent to Opaque

Opaque

Density

2.5-2.52 g/cm³

2.11-2.36 g/cm³

Thermal Properties

Specific Heat Capacity

Not Available

2.39 kJ/Kg K

Resistance

Heat Resistant, Impact Resistant

Heat Resistant, Pressure Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

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

India, Indonesia, Japan, Nepal, South Korea

Africa

Egypt, Ethiopia, Ghana, South Africa

Egypt, Ethiopia, Morocco, Namibia, South Africa, Tanzania

Europe

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

Austria, Finland, Germany, Italy, Romania, Turkey, United Kingdom

Others

Greenland

Not Yet Found

Deposits in Western Continents

North America

Canada, Cuba, Jamaica, USA

Mexico, USA

South America

Bolivia, Brazil, Colombia, Ecuador, Paraguay

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

Deposits in Oceania Continent

Australia

New South Wales, New Zealand, Western Australia

Summary >>

<< Reserves

All about Porphyry and Andesite Properties

Know all about Porphyry and Andesite properties here. All properties of rocks are important as they define the type of rock and its application. Porphyry and Andesite belong to Igneous Rocks.Texture of Porphyry is Porphyritic whereas that of Andesite is Aphanitic to Porphyritic. Porphyry appears Dull and Andesite appears Dull and Soft. The luster of Porphyry is dull while that of Andesite is vitreous. Porphyry is available in black, brown, colourless, green, grey, red, rust, white colors whereas Andesite is available in bluish - grey, grey, pink, yellow colors. The commercial uses of Porphyry are creating artwork, gemstone, jewelry and that of Andesite are commemorative tablets, creating artwork.