Felsite

Porphyry

Felsite and Porphyry

Felsite

Porphyry

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Definition

Felsite is a very fine grained volcanic rock that may or may not contain larger crystals and light colored rock that typically requires petrographic examination or chemical analysis for more precise definition

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

History

Origin

Egypt

Discoverer

Unknown

Etymology

From English feldspar and -ite

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

Class

Igneous Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Durable Rock, Hard Rock

Family

Group

Volcanic

Plutonic

Other Categories

Fine Grained Rock, Opaque Rock

Texture

Arborescent Patterned, Vitreous

Porphyritic

Color

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

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

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Layered, Banded, Veined and Shiny

Dull

Uses

Architecture

Interior Uses

Decorative Aggregates, Flooring, Interior Decoration

Decorative Aggregates, Interior Decoration

Exterior Uses

Paving Stone, Garden Decoration

Garden Decoration, Paving Stone

Other Architectural Uses

Curbing

Industry

Construction Industry

Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points

Construction Aggregate

Medical Industry

Surgery

Antiquity Uses

Artifacts

Artifacts, Monuments, Sculpture

Other Uses

Commercial Uses

Mirror, Jewelry

Creating Artwork, Gemstone, Jewelry

Types

Igneous rock

Rhomb Porphyry

Features

Available in Lots of Colors and Patterns, Clasts are smooth to touch, Splintery, Very fine grained rock

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

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Formation

Felsite 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.

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.

Composition

Mineral Content

Feldspar, Iron Oxides

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

Compound Content

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

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

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism

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

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Biological Weathering, Chemical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Glacier Erosion, Water Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Properties

Physical Properties

Hardness

5-5.56-7

1 7

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Grain Size

Fine Grained

Fracture

Conchoidal

Irregular

Streak

White

Porosity

Very Less Porous

Less Porous

Luster

Vitreous

Dull

Compressive Strength

0.15 N/mm²150.00 N/mm²

0.15 450

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Cleavage

Toughness

1.7

Specific Gravity

2.6-2.72.5-4

0 8.4

👆🏻

Transparency

Translucent

Translucent to Opaque

Density

2.6 g/cm³2.5-2.52 g/cm³

0 1400

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Thermal Properties

Specific Heat Capacity

0.92 kJ/Kg K0.71 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant

Reserves

Deposits in Eastern Continents

Asia

Afghanistan, Indonesia, Japan, Russia

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

Africa

Kenya

Egypt, Ethiopia, Ghana, South Africa

Europe

Greece, Hungary, Iceland, Italy, Turkey

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

Others

Greenland

Deposits in Western Continents

North America

Canada, Mexico, USA

Canada, Cuba, Jamaica, USA

South America

Argentina, Chile, Ecuador, Peru

Bolivia, Brazil, Colombia, Ecuador, Paraguay

Deposits in Oceania Continent

Australia

New Zealand

New South Wales, New Zealand, Western Australia

All about Felsite and Porphyry Properties

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