Dacite

Tephrite

Dacite and Tephrite

Dacite

Tephrite

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1 Definition

1.1 Definition

Dacite is a volcanic igneous rock which is rintermediate in composition between andesite and rhyolite

Tephrite is an aphanitic to porphyritic textured, volcanic igneous rock

1.2 History

1.2.1 Origin

Romania and Moldova, Europe

Germany

1.2.2 Discoverer

Unknown

Van Tooren

1.3 Etymology

From Dacia, a province of the Roman Empire which lay between the Danube River and Carpathian Mountains where the rock was first described

From Greek tephra, ashes from Indo-European base, to burn

1.4 Class

Igneous Rocks

1.4.1 Sub-Class

Durable Rock, Soft Rock

Durable Rock, Hard Rock

1.5 Family

1.5.1 Group

Volcanic

1.6 Other Categories

Fine Grained Rock, Medium Grained Rock, Opaque Rock

Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock

2 Texture

2.1 Texture

Aphanitic to Porphyritic

2.2 Color

Bluish - Grey, Brown, Grey, Light to Dark Grey

Black, Brown, Colourless, Green, Grey, White

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

Vesicular

3 Uses

3.1 Architecture

3.1.1 Interior Uses

Decorative Aggregates, Entryways, Interior Decoration

Decorative Aggregates, Flooring, Homes, Interior Decoration

3.1.2 Exterior Uses

As Building Stone, Paving Stone, Garden Decoration

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

3.1.3 Other Architectural Uses

Curbing

3.2 Industry

3.2.1 Construction Industry

As Dimension Stone, Construction Aggregate, for Road Aggregate, Landscaping

Landscaping

3.2.2 Medical Industry

Not Yet Used

3.3 Antiquity Uses

Artifacts

Artifacts, Sculpture

3.4 Other Uses

3.4.1 Commercial Uses

Commemorative Tablets, Creating Artwork

Production of Lime, Soil Conditioner

4 Types

4.1 Types

Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite

Not Available

4.2 Features

Host Rock for Lead, Is one of the oldest rock

Host Rock for Lead

4.3 Archaeological Significance

4.3.1 Monuments

Not Yet Used

4.3.2 Famous Monuments

Not Applicable

4.3.3 Sculpture

Not Yet Used

Used

4.3.4 Famous Sculptures

Not Applicable

Data Not Available

4.3.5 Pictographs

Used

Not Used

4.3.6 Petroglyphs

Used

Not Used

4.3.7 Figurines

Not Yet Used

Used

4.4 Fossils

Absent

5 Formation

5.1 Formation

Dacitic magma is formed by the subduction of young oceanic crust under a thick felsic continental plate. Further, the Oceanic crust is hydrothermally altered as quartz and sodium are added.

Tephrite 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.

5.2 Composition

5.2.1 Mineral Content

Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon

Alkali feldspar, Nepheline, Plagioclase, Pyroxene

5.2.2 Compound Content

Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide

CaO, Carbon Dioxide, MgO, Silicon Dioxide

5.3 Transformation

5.3.1 Metamorphism

✔ ✘

5.3.2 Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism

Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism

5.3.3 Weathering

✔ ✘

5.3.4 Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

5.3.5 Erosion

✔ ✘

5.3.6 Types of Erosion

Chemical Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion

6 Properties

6.1 Physical Properties

6.1.1 Hardness

2-2.256.5

1 7

6.1.2 Grain Size

Medium to Fine Coarse Grained

6.1.3 Fracture

Conchoidal

Uneven

6.1.4 Streak

White

Bluish Black

6.1.5 Porosity

Less Porous

Very Less Porous

6.1.6 Luster

Subvitreous to Dull

6.1.7 Compressive Strength

NA90.00 N/mm²

0.15 450

6.1.8 Cleavage

Perfect

Crenulation and Pervasive

6.1.9 Toughness

Not Available

2.4

6.1.10 Specific Gravity

2.86-2.872.86

0 8.4

6.1.11 Transparency

Translucent

Opaque

6.1.12 Density

2.77-2.771 g/cm³2.8-2.9 g/cm³

0 1400

6.2 Thermal Properties

6.2.1 Specific Heat Capacity

0.92 kJ/Kg K0.92 kJ/Kg K

0.14 3.2

6.2.2 Resistance

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Heat Resistant, Impact Resistant

7 Reserves

7.1 Deposits in Eastern Continents

7.1.1 Asia

Not Yet Found

7.1.2 Africa

Not Yet Found

Namibia, Uganda

7.1.3 Europe

France, Greece, Romania, Scotland, Spain

Germany, Hungary, Italy, Portugal, Spain

7.1.4 Others

Not Yet Found

7.2 Deposits in Western Continents

7.2.1 North America

USA

7.2.2 South America

Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela

Not Yet Found

7.3 Deposits in Oceania Continent

7.3.1 Australia

New Zealand, South Australia, Western Australia

New Zealand, Western Australia

All about Dacite and Tephrite Properties

Know all about Dacite and Tephrite properties here. All properties of rocks are important as they define the type of rock and its application. Dacite and Tephrite belong to Igneous Rocks.Texture of Dacite is Aphanitic to Porphyritic whereas that of Tephrite is Aphanitic to Porphyritic. Dacite appears Vesicular and Tephrite appears Vesicular. The luster of Dacite and Tephrite is subvitreous to dull. Dacite is available in bluish - grey, brown, grey, light to dark grey colors whereas Tephrite is available in black, brown, colourless, green, grey, white colors. The commercial uses of Dacite are commemorative tablets, creating artwork and that of Tephrite are production of lime, soil conditioner.