Porphyry

Soapstone

Porphyry and Soapstone

Porphyry

Soapstone

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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

It is a metamorphic magnesium rich rock because it is composed of the mineral talc

History

Origin

Egypt

USA

Discoverer

Unknown

Etymology

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

From 17th century, because of its greasy feel and use like a soap

Class

Igneous Rocks

Metamorphic Rocks

Sub-Class

Durable Rock, Hard Rock

Durable Rock, Soft Rock

Family

Group

Plutonic

Other Categories

Fine Grained Rock, Opaque Rock

Texture

Porphyritic

Polished

Color

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

Black, Black to Grey, Green, Grey

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull

Dull, Banded and Foilated

Uses

Architecture

Interior Uses

Decorative Aggregates, Interior Decoration

Bathrooms, Decorative Aggregates, Homes, Interior Decoration

Exterior Uses

Garden Decoration, Paving Stone

As Facing Stone, Garden Decoration

Other Architectural Uses

Curbing

Industry

Construction Industry

Construction Aggregate

Manufacture of Magnesium and Dolomite Refractories

Medical Industry

Taken as a Supplement for Calcium or Magnesium

Antiquity Uses

Artifacts, Monuments, Sculpture

Artifacts, Jewellery, Monuments, Sculpture

Other Uses

Commercial Uses

Creating Artwork, Gemstone, Jewelry

Cemetery Markers, Creating Artwork, Gemstone, Jewelry, Manufacture of Soap, Solvents, Dyes, Plastics and Fibres, Production of Lime, Source of Magnesia (MgO)

Types

Rhomb Porphyry

Metamorphic 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

Christ the Redeemer in Rio de Janeiro, Stonehenge in English county of Wiltshire

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.

Soapstone is a talc-schist, which is a type of metamorphic rock and it is largely composed of the mineral talc and is thus rich inmagnesium.

Composition

Mineral Content

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

Albite, Apatite, Biotite, Calcite, Carbonate, Clay Minerals, Hornblende, Ilmenite, Micas, Plagioclase, Pyroxene, Quartz

Compound Content

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

CaO, Mg, MgO

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

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Properties

Physical Properties

Hardness

6-71

1 7

👆🏻

Grain Size

Fine Grained

Fracture

Irregular

Conchoidal

Streak

White

Black

Porosity

Less Porous

Luster

Dull

Greasy

Compressive Strength

150.00 N/mm²225.00 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/cm³2.8-2.9 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.71 kJ/Kg K0.88 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant

Heat Resistant, Pressure Resistant

Reserves

Deposits in Eastern Continents

Asia

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

China, India, Indonesia, Japan, North Korea, Russia, Saudi Arabia, Singapore, South Korea, Sri Lanka, Tajikistan, Thailand

Africa

Egypt, Ethiopia, Ghana, South Africa

Egypt, Ethiopia, Ghana, South Africa, Western Africa

Europe

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

Austria, England, Finland, France, Germany, Greece, Spain, Sweden, Switzerland, United Kingdom

Others

Greenland

Deposits in Western Continents

North America

Canada, Cuba, Jamaica, USA

Canada, USA

South America

Bolivia, Brazil, Colombia, Ecuador, Paraguay

Colombia

Deposits in Oceania Continent

Australia

New South Wales, New Zealand, Western Australia

Central Australia, New Zealand, Queensland

All about Porphyry and Soapstone Properties

Know all about Porphyry and Soapstone properties here. All properties of rocks are important as they define the type of rock and its application. Porphyry belongs to Igneous Rocks while Soapstone belongs to Metamorphic Rocks.Texture of Porphyry is Porphyritic whereas that of Soapstone is Polished. Porphyry appears Dull and Soapstone appears Dull, Banded and Foilated. The luster of Porphyry is dull while that of Soapstone is greasy. Porphyry is available in black, brown, green, grey, red, rust, white colors whereas Soapstone is available in black, black to grey, green, grey colors. The commercial uses of Porphyry are creating artwork, gemstone, jewelry and that of Soapstone are cemetery markers, creating artwork, gemstone, jewelry, manufacture of soap, solvents, dyes, plastics and fibres, production of lime, source of magnesia (mgo).