Porphyry

Dacite

Porphyry and Dacite

Porphyry

Dacite

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1 Definition

1.1 Definition

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

Dacite is a volcanic igneous rock which is rintermediate in composition between andesite and rhyolite

1.2 History

1.2.1 Origin

Egypt

Romania and Moldova, Europe

1.2.2 Discoverer

Unknown

1.3 Etymology

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

From Dacia, a province of the Roman Empire which lay between the Danube River and Carpathian Mountains where the rock was first described

1.4 Class

Igneous Rocks

1.4.1 Sub-Class

Durable Rock, Hard Rock

Durable Rock, Soft Rock

1.5 Family

1.5.1 Group

Plutonic

Volcanic

1.6 Other Categories

Fine Grained Rock, Opaque Rock

Fine Grained Rock, Medium Grained Rock, Opaque Rock

2 Texture

2.1 Texture

Porphyritic

Aphanitic to Porphyritic

2.2 Color

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

Bluish - Grey, Brown, Grey, Light to Dark Grey

2.3 Maintenance

Less

2.4 Durability

Durable

2.4.1 Water Resistant

✔ ✘

81% Igneous Rocks Rocks have it !

✔ ✘

81% Igneous Rocks Rocks have it !

2.4.2 Scratch Resistant

✔ ✘

86% Igneous Rocks Rocks have it !

✔ ✘

86% Igneous Rocks Rocks have it !

2.4.3 Stain Resistant

✔ ✘

66% Igneous Rocks Rocks have it !

✔ ✘

66% Igneous Rocks Rocks have it !

2.4.4 Wind Resistant

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49% Igneous Rocks Rocks have it !

✔ ✘

49% Igneous Rocks Rocks have it !

2.4.5 Acid Resistant

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48% Igneous Rocks Rocks have it !

✔ ✘

48% Igneous Rocks Rocks have it !

2.5 Appearance

Dull

Vesicular

3 Uses

3.1 Architecture

3.1.1 Interior Uses

Decorative Aggregates, Interior Decoration

Decorative Aggregates, Entryways, Interior Decoration

3.1.2 Exterior Uses

Garden Decoration, Paving Stone

As Building Stone, Paving Stone, Garden Decoration

3.1.3 Other Architectural Uses

Curbing

3.2 Industry

3.2.1 Construction Industry

Construction Aggregate

As Dimension Stone, Construction Aggregate, for Road Aggregate, Landscaping

3.2.2 Medical Industry

Not Yet Used

3.3 Antiquity Uses

Artifacts, Monuments, Sculpture

Artifacts

3.4 Other Uses

3.4.1 Commercial Uses

Creating Artwork, Gemstone, Jewelry

Commemorative Tablets, Creating Artwork

4 Types

4.1 Types

Rhomb Porphyry

Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite

4.2 Features

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

Host Rock for Lead, Is one of the oldest rock

4.3 Archaeological Significance

4.3.1 Monuments

Used

Not Yet Used

4.3.2 Famous Monuments

Data Not Available

Not Applicable

4.3.3 Sculpture

Used

Not Yet Used

4.3.4 Famous Sculptures

Data Not Available

Not Applicable

4.3.5 Pictographs

Not Used

Used

4.3.6 Petroglyphs

Not Used

Used

4.3.7 Figurines

Used

Not Yet Used

4.4 Fossils

Absent

5 Formation

5.1 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.

Dacitic magma is formed by the subduction of young oceanic crust under a thick felsic continental plate. Further, the Oceanic crust is hydrothermally altered as quartz and sodium are added.

5.2 Composition

5.2.1 Mineral Content

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

Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon

5.2.2 Compound Content

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

Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide

5.3 Transformation

5.3.1 Metamorphism

✔ ✘

97% Igneous Rocks Rocks have it !

✔ ✘

97% Igneous Rocks Rocks have it !

5.3.2 Types of Metamorphism

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

Burial Metamorphism, Cataclastic Metamorphism

5.3.3 Weathering

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99% Igneous Rocks Rocks have it !

✔ ✘

99% Igneous Rocks Rocks have it !

5.3.4 Types of Weathering

Biological Weathering, Chemical Weathering, Not Registered

Biological Weathering, Chemical Weathering, Mechanical Weathering

5.3.5 Erosion

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92% Igneous Rocks Rocks have it !

✔ ✘

92% Igneous Rocks Rocks have it !

5.3.6 Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Chemical Erosion

6 Properties

6.1 Physical Properties

6.1.1 Hardness

6-7

2-2.25

6.1.2 Grain Size

Fine Grained

Medium to Fine Coarse Grained

6.1.3 Fracture

Irregular

Conchoidal

6.1.4 Streak

White

6.1.5 Porosity

Less Porous

6.1.6 Luster

Dull

Subvitreous to Dull

6.1.7 Compressive Strength

What Is Flint

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▼

Not Available

Rank: N/A (Overall)▶

Not Available

Rank: N/A (Overall)▶

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What Is Obsidian

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▶

175 (What Is Grani..)

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6.1.8 Cleavage

Imperfect

Perfect

6.1.9 Toughness

1.7

Not Available

6.1.10 Specific Gravity

2.5-4

2.86-2.87

6.1.11 Transparency

Translucent to Opaque

Translucent

6.1.12 Density

2.5-2.52 g/cm³

2.77-2.771 g/cm³

6.2 Thermal Properties

6.2.1 Specific Heat Capacity

What Is Banded ..

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▶

▼

Not Available

Rank: N/A (Overall)▶

0.92 kJ/Kg K

Rank: 10 (Overall)▶

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What Is Granulite

⊕

▶

1.09 (What Is Trave..)

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6.2.2 Resistance

Heat Resistant, Impact Resistant

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

7 Reserves

7.1 Deposits in Eastern Continents

7.1.1 Asia

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

Not Yet Found

7.1.2 Africa

Egypt, Ethiopia, Ghana, South Africa

Not Yet Found

7.1.3 Europe

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

France, Greece, Romania, Scotland, Spain

7.1.4 Others

Greenland

Not Yet Found

7.2 Deposits in Western Continents

7.2.1 North America

Canada, Cuba, Jamaica, USA

USA

7.2.2 South America

Bolivia, Brazil, Colombia, Ecuador, Paraguay

Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela

7.3 Deposits in Oceania Continent

7.3.1 Australia

New South Wales, New Zealand, Western Australia

New Zealand, South Australia, Western Australia

All about Porphyry and Dacite Properties

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