Porphyry

Tephrite

Porphyry and Tephrite

Porphyry

Tephrite

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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

Tephrite is an aphanitic to porphyritic textured, volcanic igneous rock

History

Origin

Egypt

Germany

Discoverer

Unknown

Van Tooren

Etymology

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

From Greek tephra, ashes from Indo-European base, to burn

Class

Igneous Rocks

Sub-Class

Durable Rock, Hard Rock

Family

Group

Plutonic

Volcanic

Other Categories

Fine Grained Rock, Opaque Rock

Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock

Texture

Porphyritic

Aphanitic to Porphyritic

Color

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

Black, Brown, Green, Grey, White

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, Office Buildings

Other Architectural Uses

Curbing

Industry

Construction Industry

Construction Aggregate

Landscaping

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture

Artifacts, Sculpture

Other Uses

Commercial Uses

Creating Artwork, Gemstone, Jewelry

Production of Lime, Soil Conditioner

Types

Rhomb Porphyry

Igneous rock

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.

Tephrite is a fine-grained, hard rock which is a type of metasomatite, essentially altered basalt. It forms 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

Alkali feldspar, Nepheline, Plagioclase, Pyroxene

Compound Content

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

CaO, Carbon Dioxide, MgO, Silicon Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

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

Cataclastic Metamorphism, Contact 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

Properties

Physical Properties

Hardness

6-76.5

1 7

👆🏻

Grain Size

Fine Grained

Medium to Fine Coarse Grained

Fracture

Irregular

Uneven

Streak

White

Bluish Black

Porosity

Less Porous

Very Less Porous

Luster

Dull

Subvitreous to Dull

Compressive Strength

150.00 N/mm²90.00 N/mm²

0.15 450

👆🏻

Cleavage

Crenulation and Pervasive

Toughness

1.7

2.4

Specific Gravity

2.5-42.86

0 8.4

👆🏻

Transparency

Translucent to Opaque

Opaque

Density

2.5-2.52 g/cm³2.8-2.9 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.71 kJ/Kg K0.92 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

Africa

Egypt, Ethiopia, Ghana, South Africa

Namibia, Uganda

Europe

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

Germany, Hungary, Italy, Portugal, Spain

Others

Greenland

Deposits in Western Continents

North America

Canada, Cuba, Jamaica, USA

USA

South America

Bolivia, Brazil, Colombia, Ecuador, Paraguay

Deposits in Oceania Continent

Australia

New South Wales, New Zealand, Western Australia

New Zealand, Western Australia

All about Porphyry and Tephrite Properties

Know all about Porphyry and Tephrite properties here. All properties of rocks are important as they define the type of rock and its application. Porphyry and Tephrite belong to Igneous Rocks.Texture of Porphyry is Porphyritic whereas that of Tephrite is Aphanitic to Porphyritic. Porphyry appears Dull and Tephrite appears Vesicular. The luster of Porphyry is dull while that of Tephrite is subvitreous to dull. Porphyry and Tephrite are available in black, brown, green, grey, red, rust, white colors. The commercial uses of Porphyry are creating artwork, gemstone, jewelry and that of Tephrite are production of lime, soil conditioner.