Pseudotachylite

Rapakivi Granite

Pseudotachylite and Rapakivi Granite

Pseudotachylite

Rapakivi Granite

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Definition

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

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

History

Origin

USA

Finland, Europe

Discoverer

Unknown

Jakob Sederholm

Etymology

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

From Finnish Rapakivi which stands for crumbly rock

Class

Metamorphic Rocks

Igneous Rocks

Sub-Class

Durable Rock, Hard Rock

Family

Group

Plutonic

Other Categories

Fine Grained Rock, Opaque Rock

Coarse Grained Rock, Opaque Rock

Texture

Quench

Granular, Phaneritic

Color

Black, Brown, Green, Grey, Pink, White

Black, Grey, Orange, Pink, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull and Soft

Veined or Pebbled

Uses

Architecture

Interior Uses

Decorative Aggregates, Entryways, Interior Decoration

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

Exterior Uses

As Building Stone, As Facing Stone, Garden Decoration

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

Other Architectural Uses

Curbing

Industry

Construction Industry

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

As Dimension Stone

Medical Industry

Antiquity Uses

Artifacts, Monuments

Artifacts, Monuments, Sculpture, Small Figurines

Other Uses

Commercial Uses

Creating Artwork, Gemstone

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

Types

Cataclastic rock

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

Features

Host Rock for Lead

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

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Formation

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.

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

Composition

Mineral Content

Iron Oxides, Pyroxene, Quartz, Stishovite, Sulfides

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

Compound Content

Carbon Dioxide, Silicon Dioxide, Sulfur Dioxide, Sulphur

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

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

76-7

1 7

👆🏻

Grain Size

Very fine-grained

Large and Coarse Grained

Fracture

Uneven

Streak

Light to dark brown

White

Porosity

Less Porous

Luster

Vitreous

Dull to Grainy with Sporadic parts Pearly and Vitreous

Compressive Strength

60.00 N/mm²175.00 N/mm²

0.15 450

👆🏻

Cleavage

Toughness

Specific Gravity

2.46-2.862.6-2.7

0 8.4

👆🏻

Transparency

Transparent to Translucent

Opaque

Density

2.7-2.9 g/cm³2.6-2.8 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.92 kJ/Kg K0.79 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant

Heat Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

South Korea

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

Africa

Western Africa

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

Europe

Great Britain, Switzerland

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

Others

Deposits in Western Continents

North America

Canada, USA

South America

Deposits in Oceania Continent

Australia

Central Australia, Western Australia

All about Pseudotachylite and Rapakivi Granite Properties

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