Hornfels

Dacite

Hornfels and Dacite

Hornfels

Dacite

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1 Definition

1.1 Definition

Hornfels is a metamorphic rock formed by the contact between mudstone or other clay rich rock, and a hot igneous body, and represents a heat altered equivalent of the original rock

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

1.2 History

1.2.1 Origin

New Zealand

Romania and Moldova, Europe

1.2.2 Discoverer

Unknown

1.3 Etymology

From German which means hornstone

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

1.4 Class

Metamorphic Rocks

Igneous Rocks

1.4.1 Sub-Class

Durable Rock, Soft Rock

1.5 Family

1.5.1 Group

Not Applicable

Volcanic

1.6 Other Categories

Fine Grained Rock, Opaque Rock

Fine Grained Rock, Medium Grained Rock, Opaque Rock

2 Texture

2.1 Texture

Granular, Platy

Aphanitic to Porphyritic

2.2 Color

Brown, Dark Greenish - Grey, Green, Reddish Brown

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

2.3 Maintenance

Less

2.4 Durability

Durable

2.4.1 Water Resistant

✔ ✘

81% Metamorphic Rocks Rocks have it !

✔ ✘

81% Igneous Rocks Rocks have it !

2.4.2 Scratch Resistant

✔ ✘

65% Metamorphic Rocks Rocks have it !

✔ ✘

86% Igneous Rocks Rocks have it !

2.4.3 Stain Resistant

✔ ✘

42% Metamorphic Rocks Rocks have it !

✔ ✘

66% Igneous Rocks Rocks have it !

2.4.4 Wind Resistant

✔ ✘

19% Metamorphic Rocks Rocks have it !

✔ ✘

49% Igneous Rocks Rocks have it !

2.4.5 Acid Resistant

✔ ✘

15% Metamorphic Rocks Rocks have it !

✔ ✘

48% Igneous Rocks Rocks have it !

2.5 Appearance

Dull

Vesicular

3 Uses

3.1 Architecture

3.1.1 Interior Uses

Decorative Aggregates, Flooring, Homes, Interior Decoration

Decorative Aggregates, Entryways, Interior Decoration

3.1.2 Exterior Uses

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

As Building Stone, Paving Stone, Garden Decoration

3.1.3 Other Architectural Uses

Curbing

3.2 Industry

3.2.1 Construction Industry

for Road Aggregate, Roadstone

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

3.2.2 Medical Industry

Not Yet Used

3.3 Antiquity Uses

Artifacts, Monuments

Artifacts

3.4 Other Uses

3.4.1 Commercial Uses

Cemetery Markers, Commemorative Tablets, Creating Artwork

Commemorative Tablets, Creating Artwork

4 Types

4.1 Types

Biotite hornfels

Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite

4.2 Features

Smooth to touch

Host Rock for Lead, Is one of the oldest rock

4.3 Archaeological Significance

4.3.1 Monuments

Used

Not Yet Used

4.3.2 Famous Monuments

Data Not Available

Not Applicable

4.3.3 Sculpture

Not Yet Used

4.3.4 Famous Sculptures

Not Applicable

4.3.5 Pictographs

Used

4.3.6 Petroglyphs

Used

4.3.7 Figurines

Not Yet Used

4.4 Fossils

Absent

5 Formation

5.1 Formation

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

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.

5.2 Composition

5.2.1 Mineral Content

Andalusite

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

5.2.2 Compound Content

Fe, Mg

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

5.3 Transformation

5.3.1 Metamorphism

✔ ✘

50% Metamorphic Rocks Rocks have it !

✔ ✘

97% Igneous Rocks Rocks have it !

5.3.2 Types of Metamorphism

Not Applicable

Burial Metamorphism, Cataclastic Metamorphism

5.3.3 Weathering

✔ ✘

65% Metamorphic Rocks Rocks have it !

✔ ✘

99% Igneous Rocks Rocks have it !

5.3.4 Types of Weathering

Biological Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

5.3.5 Erosion

✔ ✘

77% Metamorphic Rocks Rocks have it !

✔ ✘

92% Igneous Rocks Rocks have it !

5.3.6 Types of Erosion

Chemical Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion

Chemical Erosion

6 Properties

6.1 Physical Properties

6.1.1 Hardness

2-3

2-2.25

6.1.2 Grain Size

Fine Grained

Medium to Fine Coarse Grained

6.1.3 Fracture

Conchoidal

6.1.4 Streak

Unknown

White

6.1.5 Porosity

Highly Porous

Less Porous

6.1.6 Luster

Shiny

Subvitreous to Dull

6.1.7 Compressive Strength

What Is Flint

⊕

▶

▼

5.80 N/mm²

Rank: 31 (Overall)▶

Not Available

Rank: N/A (Overall)▶

▲

What Is Obsidian

⊕

▶

175 (What Is Grani..)

◀ ▶ ADD ⊕

6.1.8 Cleavage

Perfect

6.1.9 Toughness

Not Yet Found

Not Available

6.1.10 Specific Gravity

3.4-3.9

2.86-2.87

6.1.11 Transparency

Opaque

Translucent

6.1.12 Density

0.25-0.30 g/cm³

2.77-2.771 g/cm³

6.2 Thermal Properties

6.2.1 Specific Heat Capacity

What Is Banded ..

⊕

▶

▼

0.84 kJ/Kg K

Rank: 15 (Overall)▶

0.92 kJ/Kg K

Rank: 10 (Overall)▶

▲

What Is Granulite

⊕

▶

1.09 (What Is Trave..)

◀ ▶ ADD ⊕

6.2.2 Resistance

Heat Resistant, Impact Resistant, Pressure Resistant

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

7 Reserves

7.1 Deposits in Eastern Continents

7.1.1 Asia

Bangladesh, Bhutan, China, India, North Korea, Qatar, Russia, Saudi Arabia, South Korea, Thailand

Not Yet Found

7.1.2 Africa

Cameroon, East Africa, Tanzania, Western Africa

Not Yet Found

7.1.3 Europe

United Kingdom

France, Greece, Romania, Scotland, Spain

7.1.4 Others

Not Yet Found

7.2 Deposits in Western Continents

7.2.1 North America

Canada, USA

USA

7.2.2 South America

Bolivia, Brazil, Colombia, Ecuador

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

7.3 Deposits in Oceania Continent

7.3.1 Australia

New South Wales, New Zealand, Queensland, Western Australia

New Zealand, South Australia, Western Australia

All about Hornfels and Dacite Properties

Know all about Hornfels and Dacite properties here. All properties of rocks are important as they define the type of rock and its application. Hornfels belongs to Metamorphic Rocks while Dacite belongs to Igneous Rocks.Texture of Hornfels is Granular, Platy whereas that of Dacite is Aphanitic to Porphyritic. Hornfels appears Dull and Dacite appears Vesicular. The luster of Hornfels is shiny while that of Dacite is subvitreous to dull. Hornfels is available in brown, dark greenish - grey, green, reddish brown colors whereas Dacite is available in bluish - grey, brown, grey, light to dark grey colors. The commercial uses of Hornfels and Dacite are cemetery markers, commemorative tablets, creating artwork.