Rapakivi Granite

Pseudotachylite

Rapakivi Granite and Pseudotachylite

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Definition

Rapakivi Granite is a hornblende-biotite Granite containing large rounded crystals of orthoclase which are mantled with oligoclase

Very fine grained fault rock which is composed of glassy matrix that often contains inclusions of wall-rock fragments.

History

Origin

Finland, Europe

USA

Discoverer

Jakob Sederholm

Unknown

Etymology

From Finnish Rapakivi which stands for crumbly rock

From pseudo- +‎ tachylite, a glassy rock generated by frictional heat within faults.

Class

Igneous Rocks

Metamorphic Rocks

Sub-Class

Durable Rock, Hard Rock

Family

Group

Plutonic

Other Categories

Coarse Grained Rock, Opaque Rock

Fine Grained Rock, Opaque Rock

Texture

Granular, Phaneritic

Quench

Color

Black, Grey, Orange, Pink, White

Black, Brown, Green, Grey, Pink, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Veined or Pebbled

Dull and Soft

Uses

Architecture

Interior Uses

Bathrooms, Countertops, Decorative Aggregates, Entryways, Floor Tiles, Flooring, Homes, Hotels, Interior Decoration, Kitchens, Stair Treads

Decorative Aggregates, Entryways, Interior Decoration

Exterior Uses

As Building Stone, As Facing Stone, Office Buildings, Paving Stone, Resorts

As Building Stone, As Facing Stone, Garden Decoration

Other Architectural Uses

Curbing

Industry

Construction Industry

As Dimension Stone

As Dimension Stone, Cement Manufacture, for Road Aggregate, Making natural cement

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture, Small Figurines

Artifacts, Monuments

Other Uses

Commercial Uses

Cemetery Markers, Commemorative Tablets, Creating Artwork, Curling, Laboratory bench tops, Tombstones

Creating Artwork, Gemstone

Types

Igneous Protolith Granite, Sedimentary Protolith Granite, Mantle Granite, Anorogenic Granite and Hybrid Granite

Cataclastic rock

Features

Available in Lots of Colors and Patterns, It is One of the Oldest, Strongest and Hardest Rock

Host Rock for Lead

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Formation

Granite is an igneous rock which is very hard, crystalline and is visibly homogeneous in texture and forms by melting of continental rocks

Due to change in environmental conditions, rocks are heated and pressurized deep inside the Earth's surface. Pseudotachylite is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.

Composition

Mineral Content

Amphibole, Biotite, Feldspar, Hornblade, Micas, Muscovite or Illite, Plagioclase, Pyroxene, Quartz

Iron Oxides, Pyroxene, Quartz, Stishovite, Sulfides

Compound Content

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

Carbon Dioxide, Silicon Dioxide, Sulfur Dioxide, Sulphur

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Coastal Erosion, Water Erosion, Wind Erosion

Properties

Physical Properties

Hardness

6-77

1 7

👆🏻

Grain Size

Large and Coarse Grained

Very fine-grained

Fracture

Uneven

Streak

White

Light to dark brown

Porosity

Less Porous

Luster

Dull to Grainy with Sporadic parts Pearly and Vitreous

Vitreous

Compressive Strength

175.00 N/mm²60.00 N/mm²

0.15 450

👆🏻

Cleavage

Toughness

Specific Gravity

2.6-2.72.46-2.86

0 8.4

👆🏻

Transparency

Opaque

Transparent to Translucent

Density

2.6-2.8 g/cm³2.7-2.9 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.79 kJ/Kg K0.92 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Wear Resistant

Heat Resistant

Reserves

Deposits in Eastern Continents

Asia

China, India, Iran, Saudi Arabia, Sri Lanka, Taiwan, Thailand, Turkey, Vietnam

South Korea

Africa

Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa

Western Africa

Europe

Austria, Belgium, Finland, France, Germany, Italy, Norway, Sardinia, Spain, Switzerland, The Czech Republic

Great Britain, Switzerland

Others

Deposits in Western Continents

North America

Canada, USA

South America

Deposits in Oceania Continent

Australia

Central Australia, Western Australia

All about Rapakivi Granite and Pseudotachylite Properties

Know all about Rapakivi Granite and Pseudotachylite properties here. All properties of rocks are important as they define the type of rock and its application. Rapakivi Granite belongs to Igneous Rocks while Pseudotachylite belongs to Metamorphic Rocks.Texture of Rapakivi Granite is Granular, Phaneritic whereas that of Pseudotachylite is Quench. Rapakivi Granite appears Veined or Pebbled and Pseudotachylite appears Dull and Soft. The luster of Rapakivi Granite is dull to grainy with sporadic parts pearly and vitreous while that of Pseudotachylite is vitreous. Rapakivi Granite is available in black, grey, orange, pink, white colors whereas Pseudotachylite is available in black, brown, green, grey, pink, white colors. The commercial uses of Rapakivi Granite are cemetery markers, commemorative tablets, creating artwork, curling, laboratory bench tops, tombstones and that of Pseudotachylite are creating artwork, gemstone.