Porphyry

Andesite

Porphyry and Andesite

Porphyry

Andesite

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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

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

Theodor von Gümbel

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, Green, Grey, Red, Rust, White

Bluish - Grey, Grey, Pink, Yellow

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

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

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

Famous Monuments

Middle of the Earth in Ecuador

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.

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

✔ ✘

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, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Properties

Physical Properties

Hardness

6-77

1 7

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Grain Size

Fine Grained

Very fine-grained

Fracture

Irregular

Uneven

Streak

White

Porosity

Less Porous

Luster

Dull

Vitreous

Compressive Strength

150.00 N/mm²225.00 N/mm²

0.15 450

👆🏻

Cleavage

Toughness

1.7

1.1

Specific Gravity

2.5-42.5-2.8

0 8.4

👆🏻

Transparency

Translucent to Opaque

Opaque

Density

2.5-2.52 g/cm³2.11-2.36 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.71 kJ/Kg K2.39 kJ/Kg K

0.14 3.2

👆🏻

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

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

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, 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.