Porphyry

Pumice

Porphyry and Pumice

Porphyry

Pumice

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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

Pumice is a volcanic rock that consists of highly vesicular rough textured volcanic glass, which may or may not contain crystals

History

Origin

Egypt

Spain

Discoverer

Unknown

Etymology

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

From Old French pomis, from a Latin dialect variant of pumex

Class

Igneous Rocks

Sub-Class

Durable Rock, Hard Rock

Durable Rock, Medium Hardness Rock

Family

Group

Plutonic

Volcanic

Other Categories

Fine Grained Rock, Opaque Rock

Texture

Porphyritic

Vesicular

Color

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

Beige, Grey, Light Green, Light Grey, Pink, White, Yellow- grey

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull

Vesicular

Uses

Architecture

Interior Uses

Decorative Aggregates, Interior Decoration

Decorative Aggregates, Flooring, Homes, Interior Decoration

Exterior Uses

Garden Decoration, Paving Stone

As Building Stone, As Facing Stone, Garden Decoration, Paving Stone

Other Architectural Uses

Curbing

Curbing, Powder

Industry

Construction Industry

Construction Aggregate

As Dimension Stone, Cement Manufacture, for Road Aggregate, In landscaping and horticulture, Making natural cement, Production of lightweight concrete blocks

Medical Industry

As an abrasive in skin exfoliating products, In Chemical and Pharmaceutical Industry, Medicines and Cosmetics

Antiquity Uses

Artifacts, Monuments, Sculpture

Artifacts

Other Uses

Commercial Uses

Creating Artwork, Gemstone, Jewelry

As a traction material on snow-covered roads, As an abrasive in pencil erasers, Fine abrasive used for polishing, Manufacture of Soap, Solvents, Dyes, Plastics and Fibres, Used in aquariums

Types

Rhomb Porphyry

Scoria

Features

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

Host Rock for Lead

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.

Pumice rock forms when the magma cools so quickly that atoms in the melt are not able to arrange themselves into a crystalline structure.

Composition

Mineral Content

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

Aluminum Oxides, Calcite, Carbonate, Iron Oxides, Silica

Compound Content

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

Al, Aluminium Oxide, CaO, Carbon Dioxide, MgO, Silicon Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

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

Burial Metamorphism, Impact 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

6-76

1 7

👆🏻

Grain Size

Fine Grained

Fracture

Irregular

Planar

Streak

White

White, Greenish White or Grey

Porosity

Less Porous

Highly Porous

Luster

Dull

Earthy

Compressive Strength

150.00 N/mm²51.20 N/mm²

0.15 450

👆🏻

Cleavage

Perfect

Toughness

1.7

Specific Gravity

2.5-42.86

0 8.4

👆🏻

Transparency

Translucent to Opaque

Opaque

Density

2.5-2.52 g/cm³0.25-0.3 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.71 kJ/Kg K0.87 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant

Impact Resistant, Pressure Resistant

Reserves

Deposits in Eastern Continents

Asia

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

Afghanistan, Indonesia, Japan, Russia

Africa

Egypt, Ethiopia, Ghana, South Africa

Ethiopia, Kenya, Tanzania

Europe

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

Greece, Hungary, Iceland, Italy, Turkey

Others

Greenland

Deposits in Western Continents

North America

Canada, Cuba, Jamaica, USA

Bahamas, Barbados, Canada, Costa Rica, Cuba, Jamaica, Mexico, USA

South America

Bolivia, Brazil, Colombia, Ecuador, Paraguay

Argentina, Chile, Ecuador, Peru

Deposits in Oceania Continent

Australia

New South Wales, New Zealand, Western Australia

New Zealand, Western Australia

All about Porphyry and Pumice Properties

Know all about Porphyry and Pumice properties here. All properties of rocks are important as they define the type of rock and its application. Porphyry and Pumice belong to Igneous Rocks.Texture of Porphyry is Porphyritic whereas that of Pumice is Vesicular. Porphyry appears Dull and Pumice appears Vesicular. The luster of Porphyry is dull while that of Pumice is earthy. Porphyry is available in black, brown, green, grey, red, rust, white colors whereas Pumice is available in beige, grey, light green, light grey, pink, white, yellow- grey colors. The commercial uses of Porphyry are creating artwork, gemstone, jewelry and that of Pumice are as a traction material on snow-covered roads, as an abrasive in pencil erasers, fine abrasive used for polishing, manufacture of soap, solvents, dyes, plastics and fibres, used in aquariums.