Porphyry

Flint

Porphyry and Flint

Porphyry

Flint

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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

Flint is a hard type of sedimentary rock that produces a small piece of burning material when hit by steel

History

Origin

Egypt

Discoverer

Unknown

Etymology

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

From Old English flint - a type of rock mainly known for high hardness and for giving off sparks when struck

Class

Igneous Rocks

Sedimentary Rocks

Sub-Class

Durable Rock, Hard Rock

Family

Group

Plutonic

Other Categories

Fine Grained Rock, Opaque Rock

Texture

Porphyritic

Banded, Rough

Color

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

Black, Brown, Green, Grey, Red, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull

Glassy or Pearly

Uses

Architecture

Interior Uses

Decorative Aggregates, Interior Decoration

Decorative Aggregates, Homes, Interior Decoration

Exterior Uses

Garden Decoration, Paving Stone

As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone

Other Architectural Uses

Curbing

Industry

Construction Industry

Construction Aggregate

Arrowheads, Cutting Tool, Spear Points

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture

Artifacts

Other Uses

Commercial Uses

Creating Artwork, Gemstone, Jewelry

Creating Artwork, Gemstone, In fire-starting tools, Manufacture of tools, Metallurgical Flux, Jewelry, To ignite fire, Used in flintlock firearms

Types

Rhomb Porphyry

Chert and Jasper

Features

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

Clasts are smooth to touch, Easily splits into thin plates, Has High structural resistance against erosion and climate

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Present

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.

Flint is formed by the decomposition and compaction of various organisms such as sponges and diatoms under the water.

Composition

Mineral Content

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

Silicon

Compound Content

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

Silicon Dioxide

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

Chemical Erosion, Coastal Erosion, Water Erosion

Properties

Physical Properties

Hardness

6-77

1 7

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Grain Size

Fine Grained

Very fine-grained

Fracture

Irregular

Conchoidal

Streak

White

Porosity

Less Porous

Highly Porous

Luster

Dull

Vitreous

Compressive Strength

150.00 N/mm²450.00 N/mm²

0.15 450

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Cleavage

Toughness

1.7

1.5

Specific Gravity

2.5-42.5-2.8

0 8.4

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Transparency

Translucent to Opaque

Density

2.5-2.52 g/cm³2.7-2.71 g/cm³

0 1400

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Thermal Properties

Specific Heat Capacity

0.71 kJ/Kg K0.74 kJ/Kg K

0.14 3.2

👆🏻

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

Azerbaijan, China, Russia

Africa

Egypt, Ethiopia, Ghana, South Africa

Europe

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

Austria, Belgium, Cyprus, Denmark, France, Germany, Italy, Malta, Netherlands, Poland, Portugal, Romania, Spain, Sweden, Switzerland, Turkey, Ukraine, United Kingdom

Others

Greenland

Deposits in Western Continents

North America

Canada, Cuba, Jamaica, USA

USA

South America

Bolivia, Brazil, Colombia, Ecuador, Paraguay

Bolivia

Deposits in Oceania Continent

Australia

New South Wales, New Zealand, Western Australia

New Zealand, South Australia

All about Porphyry and Flint Properties

Know all about Porphyry and Flint properties here. All properties of rocks are important as they define the type of rock and its application. Porphyry belongs to Igneous Rocks while Flint belongs to Sedimentary Rocks.Texture of Porphyry is Porphyritic whereas that of Flint is Banded, Rough. Porphyry appears Dull and Flint appears Glassy or Pearly. The luster of Porphyry is dull while that of Flint is vitreous. Porphyry and Flint are available in black, brown, green, grey, red, rust, white colors. The commercial uses of Porphyry are creating artwork, gemstone, jewelry and that of Flint are creating artwork, gemstone, in fire-starting tools, manufacture of tools, metallurgical flux, jewelry, to ignite fire, used in flintlock firearms.