Porphyry

Comendite

Porphyry and Comendite

Porphyry

Comendite

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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

Comendite is a hard, peralkaline igneous rock, a type of light blue grey rhyolite

History

Origin

Egypt

Italy

Discoverer

Unknown

Etymology

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

Comendite derives its name from the area of Le Commende on San Pietro Island in Italy

Class

Igneous Rocks

Sub-Class

Durable Rock, Hard Rock

Family

Group

Plutonic

Volcanic

Other Categories

Fine Grained Rock, Opaque Rock

Medium Grained Rock, Opaque Rock

Texture

Porphyritic

Color

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

Blue, Bluish - Grey

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull

Foliated

Uses

Architecture

Interior Uses

Decorative Aggregates, Interior Decoration

Countertops, Decorative Aggregates, Interior Decoration

Exterior Uses

Garden Decoration, Paving Stone

As Building Stone, As Facing Stone, Garden Decoration

Other Architectural Uses

Curbing

Industry

Construction Industry

Construction Aggregate

Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate, Landscaping, Making natural cement, Raw material for the manufacture of mortar

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture

Artifacts

Other Uses

Commercial Uses

Creating Artwork, Gemstone, Jewelry

Cemetery Markers

Types

Rhomb Porphyry

Rhyolite

Features

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

Very fine grained rock, It is One of the Oldest, Strongest and Hardest 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.

Comendite is a type of Igneous rock which is formed due to cooling and solidification of lava or magma. It may form with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.

Composition

Mineral Content

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

Albite, Amphibole, Quartz

Compound Content

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

Al, Fe, Potassium Oxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

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

Coastal Erosion, Water Erosion

Properties

Physical Properties

Hardness

6-76-7

1 7

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Grain Size

Fine Grained

Medium Grained

Fracture

Irregular

Pervasive

Streak

White

Bluish Black

Porosity

Less Porous

Highly Porous

Luster

Dull

Compressive Strength

150.00 N/mm²92.40 N/mm²

0.15 450

👆🏻

Cleavage

Toughness

1.7

Specific Gravity

2.5-42.38

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

Reserves

Deposits in Eastern Continents

Asia

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

China

Africa

Egypt, Ethiopia, Ghana, South Africa

East Africa

Europe

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

Italy

Others

Greenland

Deposits in Western Continents

North America

Canada, Cuba, Jamaica, USA

South America

Bolivia, Brazil, Colombia, Ecuador, Paraguay

Deposits in Oceania Continent

Australia

New South Wales, New Zealand, Western Australia

Queensland

All about Porphyry and Comendite Properties

Know all about Porphyry and Comendite properties here. All properties of rocks are important as they define the type of rock and its application. Porphyry and Comendite belong to Igneous Rocks.Texture of Porphyry is Porphyritic whereas that of Comendite is Porphyritic. Porphyry appears Dull and Comendite appears Foliated. The luster of Porphyry and Comendite is dull. Porphyry is available in black, brown, green, grey, red, rust, white colors whereas Comendite is available in blue, bluish - grey colors. The commercial uses of Porphyry are creating artwork, gemstone, jewelry and that of Comendite are cemetery markers.