Porphyry

Obsidian

Porphyry and Obsidian

Porphyry

Obsidian

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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

Obsidian is a naturally occurring volcanic glass formed as an extrusive igneous rock. It is produced when felsic lava extruded from a volcano cools rapidly with minimum crystal growth

1.2 History

1.2.1 Origin

Egypt

Ethiopia

1.2.2 Discoverer

Unknown

Obsius

1.3 Etymology

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

From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius

1.4 Class

Igneous Rocks

1.4.1 Sub-Class

Durable Rock, Hard Rock

Durable Rock, Medium Hardness Rock

1.5 Family

1.5.1 Group

Plutonic

Volcanic

1.6 Other Categories

Fine Grained Rock, Opaque Rock

Opaque Rock

2 Texture

2.1 Texture

Porphyritic

Glassy

2.2 Color

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

Black, Blue, Brown, Green, Orange, Red, Tan, Yellow

2.3 Maintenance

Less

2.4 Durability

Durable

2.4.1 Water Resistant

✔ ✘

2.4.2 Scratch Resistant

✔ ✘

2.4.3 Stain Resistant

✔ ✘

2.4.4 Wind Resistant

✔ ✘

2.4.5 Acid Resistant

✔ ✘

2.5 Appearance

Dull

Shiny

3 Uses

3.1 Architecture

3.1.1 Interior Uses

Decorative Aggregates, Interior Decoration

3.1.2 Exterior Uses

Garden Decoration, Paving Stone

Garden Decoration

3.1.3 Other Architectural Uses

Curbing

Not Yet Used

3.2 Industry

3.2.1 Construction Industry

Construction Aggregate

Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points

3.2.2 Medical Industry

Not Yet Used

Surgery

3.3 Antiquity Uses

Artifacts, Monuments, Sculpture

Artifacts, Jewellery

3.4 Other Uses

3.4.1 Commercial Uses

Creating Artwork, Gemstone, Jewelry

Creating Artwork, Mirror, Used in aquariums

4 Types

4.1 Types

Rhomb Porphyry

Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian

4.2 Features

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

Blocks negativity, Helps to protect against depression

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.

When the lava is released from volcano, it undergoes a very rapid cooling which freezes the mechanisms of crystallization. The result is a volcanic glass with a uniform smooth texture.

5.2 Composition

5.2.1 Mineral Content

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

Not Available

5.2.2 Compound Content

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

Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide

5.3 Transformation

5.3.1 Metamorphism

✔ ✘

5.3.2 Types of Metamorphism

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

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism

5.3.3 Weathering

✔ ✘

5.3.4 Types of Weathering

Biological Weathering, Chemical Weathering, Not Registered

Biological Weathering, Chemical Weathering, Mechanical Weathering

5.3.5 Erosion

✔ ✘

5.3.6 Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

6 Properties

6.1 Physical Properties

6.1.1 Hardness

6-75-5.5

1 7

6.1.2 Grain Size

Fine Grained

Not Applicable

6.1.3 Fracture

Irregular

Conchoidal

6.1.4 Streak

White

6.1.5 Porosity

Less Porous

Very Less Porous

6.1.6 Luster

Dull

Vitreous

6.1.7 Compressive Strength

NA0.15 N/mm²

0.15 450

6.1.8 Cleavage

Imperfect

Non-Existent

6.1.9 Toughness

1.7

Not Available

6.1.10 Specific Gravity

2.5-42.6-2.7

0 8.4

6.1.11 Transparency

Translucent to Opaque

Translucent

6.1.12 Density

2.5-2.52 g/cm³2.6 g/cm³

0 1400

6.2 Thermal Properties

6.2.1 Specific Heat Capacity

NA0.92 kJ/Kg K

0.14 3.2

6.2.2 Resistance

Heat Resistant, Impact Resistant

7 Reserves

7.1 Deposits in Eastern Continents

7.1.1 Asia

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

Afghanistan, Indonesia, Japan, Russia

7.1.2 Africa

Egypt, Ethiopia, Ghana, South Africa

Kenya

7.1.3 Europe

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

Greece, Hungary, Iceland, Italy, Turkey

7.1.4 Others

Greenland

Not Yet Found

7.2 Deposits in Western Continents

7.2.1 North America

Canada, Cuba, Jamaica, USA

Canada, Mexico, USA

7.2.2 South America

Bolivia, Brazil, Colombia, Ecuador, Paraguay

Argentina, Chile, Ecuador, Peru

7.3 Deposits in Oceania Continent

7.3.1 Australia

New South Wales, New Zealand, Western Australia

New Zealand

All about Porphyry and Obsidian Properties

Know all about Porphyry and Obsidian properties here. All properties of rocks are important as they define the type of rock and its application. Porphyry and Obsidian belong to Igneous Rocks.Texture of Porphyry is Porphyritic whereas that of Obsidian is Glassy. Porphyry appears Dull and Obsidian appears Shiny. The luster of Porphyry is dull while that of Obsidian is vitreous. Porphyry is available in black, brown, colourless, green, grey, red, rust, white colors whereas Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors. The commercial uses of Porphyry are creating artwork, gemstone, jewelry and that of Obsidian are creating artwork, mirror, used in aquariums.