Porphyry and Scoria

Porphyry

Scoria

Definition

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

Scoria is a dark-colored extrusive igneous rock with abundant round bubble-like cavities

History

Origin

Egypt

Unknown

Discoverer

Unknown

Etymology

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

From late Middle English (denoting slag from molten metal), from Greek skōria refuse, from skōr dung

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, Colourless, Green, Grey, Red, Rust, White

Black, Brown, Dark Grey to Black, Red

Maintenance

Less

Durability

Durable

Water Resistant

Yes

Scratch Resistant

Yes

Stain Resistant

Yes

Wind Resistant

Acid Resistant

Yes

Appearance

Dull

Glassy and Vesicular

Uses

Architecture

Interior Uses

Decorative Aggregates, Interior Decoration

Exterior Uses

Garden Decoration, Paving Stone

Other Architectural Uses

Curbing

Industry

Construction Industry

Construction Aggregate

Cement Manufacture, Construction Aggregate, for Road Aggregate, In landscaping and drainage works

Medical Industry

Not Yet Used

Antiquity Uses

Artifacts, Monuments, Sculpture

Other Uses

Commercial Uses

Creating Artwork, Gemstone, Jewelry

As a traction material on snow-covered roads, Creating Artwork, High-temperature insulation, In gas barbecue grills

Types

Rhomb Porphyry

Not Available

Features

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

Available in Lots of Colors and Patterns, Generally rough to touch, Surfaces are often shiny

Archaeological Significance

Monuments

Used

Famous Monuments

Data Not Available

Sculpture

Used

Famous Sculptures

Data Not Available

Pictographs

Not Used

Used

Petroglyphs

Not Used

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.

Scoria forms when magma containing huge amount of dissolved gas flows from a volcano during an eruption.

Composition

Mineral Content

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

Apatite, Biotite, Calcite, Feldspar, Hematite, Hornblade, Ilmenite, Magnetite, Olivine, Pyroxene, Quartz, Silica

Compound Content

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

Ca, NaCl

Transformation

Metamorphism

Yes

Types of Metamorphism

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

Burial Metamorphism, Cataclastic Metamorphism, Contact 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

5-6

Grain Size

Fine Grained

Fracture

Irregular

Conchoidal

Streak

White

Porosity

Less Porous

Highly Porous

Luster

Dull

Subvitreous to Dull

Cleavage

Imperfect

Perfect

Toughness

1.7

2.1

Specific Gravity

2.5-4

Not Available

Transparency

Translucent to Opaque

Opaque

Density

2.5-2.52 g/cm³

Not Available

Thermal Properties

Resistance

Heat Resistant, Impact Resistant

Heat Resistant, Impact Resistant, Pressure Resistant, Wear 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

Not Yet Found

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

Summary >>

<< Reserves

All about Porphyry and Scoria Properties

Know all about Porphyry and Scoria properties here. All properties of rocks are important as they define the type of rock and its application. Porphyry and Scoria belong to Igneous Rocks.Texture of Porphyry is Porphyritic whereas that of Scoria is Vesicular. Porphyry appears Dull and Scoria appears Glassy and Vesicular. The luster of Porphyry is dull while that of Scoria is subvitreous to dull. Porphyry is available in black, brown, colourless, green, grey, red, rust, white colors whereas Scoria is available in black, brown, dark grey to black, red colors. The commercial uses of Porphyry are creating artwork, gemstone, jewelry and that of Scoria are as a traction material on snow-covered roads, creating artwork, high-temperature insulation, in gas barbecue grills.