Porphyry

Pegmatite

Porphyry and Pegmatite

Porphyry

Pegmatite

Add ⊕

Definition

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

Pegmatite rock is a holocrystalline, intrusive igneous rock which is composed of interlocking phaneritic crystals

History

Origin

Egypt

Discoverer

Unknown

R. J. Hauy

Etymology

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

From Greek pegma, pegmat which means- thing joined together + -ite

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

Pegmatitic

Color

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

Black, Brown, Cream, Green, Grey, Pink, Red, Rust, Silver, White, Yellow

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull

Layered, Banded, Veined and Shiny

Uses

Architecture

Interior Uses

Decorative Aggregates, Interior Decoration

Decorative Aggregates, Flooring, Interior Decoration

Exterior Uses

Garden Decoration, Paving Stone

As Building Stone, As Facing Stone, Paving Stone

Other Architectural Uses

Curbing

Industry

Construction Industry

Construction Aggregate

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

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture

Artifacts, Sculpture, Small Figurines

Other Uses

Commercial Uses

Creating Artwork, Gemstone, Jewelry

Creating Artwork, Jewelry, Source of corundum, tourmalines, beryls and topaz

Types

Rhomb Porphyry

Granite Pegmatite, Gabbro Pegmatite and Diorite Pegmatite

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, Source of corundum, tourmalines, beryls and topaz

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.

Pegmatite rock is holocrystalline, intrusive igneous rock which is formed by partial melting and dewatering during the process of metamorphism.

Composition

Mineral Content

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

Apatite, Beryl, Feldspar, Fluorite, Garnet, Lepidolite, Quartz, Silica, Spodumene, Topaz

Compound Content

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

Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, Magnesium Carbonate, MgO, Phosphorus Pentoxide

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

Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion

Properties

Physical Properties

Hardness

6-77

1 7

👆🏻

Grain Size

Fine Grained

Medium to Coarse Grained

Fracture

Irregular

Conchoidal

Streak

White

Porosity

Less Porous

Luster

Dull

Grainy, Pearly and Vitreous

Compressive Strength

150.00 N/mm²178.54 N/mm²

0.15 450

👆🏻

Cleavage

Perfect

Toughness

1.7

2.1

Specific Gravity

2.5-42.6-2.63

0 8.4

👆🏻

Transparency

Translucent to Opaque

Density

2.5-2.52 g/cm³2.6-2.65 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, Impact Resistant, Pressure Resistant

Reserves

Deposits in Eastern Continents

Asia

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

China, India, Iran, Japan, Nepal, North Korea, Russia, Saudi Arabia, South Korea

Africa

Egypt, Ethiopia, Ghana, South Africa

South Africa

Europe

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

Austria, France, Greece, Ireland, Italy, Netherlands, Slovakia, Spain, Turkey, Ukraine

Others

Greenland

Deposits in Western Continents

North America

Canada, Cuba, Jamaica, USA

Canada

South America

Bolivia, Brazil, Colombia, Ecuador, Paraguay

Brazil

Deposits in Oceania Continent

Australia

New South Wales, New Zealand, Western Australia

New South Wales, Queensland, South Australia, Western Australia

All about Porphyry and Pegmatite Properties

Know all about Porphyry and Pegmatite properties here. All properties of rocks are important as they define the type of rock and its application. Porphyry and Pegmatite belong to Igneous Rocks.Texture of Porphyry is Porphyritic whereas that of Pegmatite is Pegmatitic. Porphyry appears Dull and Pegmatite appears Layered, Banded, Veined and Shiny. The luster of Porphyry is dull while that of Pegmatite is grainy, pearly and vitreous. Porphyry is available in black, brown, green, grey, red, rust, white colors whereas Pegmatite is available in black, brown, cream, green, grey, pink, red, rust, silver, white, yellow colors. The commercial uses of Porphyry are creating artwork, gemstone, jewelry and that of Pegmatite are creating artwork, jewelry, source of corundum, tourmalines, beryls and topaz.