Dacite

Gneiss

Dacite and Gneiss

Dacite

Gneiss

Add ⊕

1 Definition

1.1 Definition

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

Gneiss is a common and widely distributed type of rock formed by high-grade regional metamorphic processes from pre-existing formations that were originally either igneous or sedimentary rocks

1.2 History

1.2.1 Origin

Romania and Moldova, Europe

Unknown

1.2.2 Discoverer

Unknown

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 the Middle High German verb gneist (to spark; so called because the rock glitters)

1.4 Class

Igneous Rocks

Metamorphic Rocks

1.4.1 Sub-Class

Durable Rock, Soft Rock

Durable Rock, Hard Rock

1.5 Family

1.5.1 Group

Volcanic

Not Applicable

1.6 Other Categories

Fine Grained Rock, Medium Grained Rock, Opaque Rock

Coarse Grained Rock, Medium Grained Rock, Opaque Rock

2 Texture

2.1 Texture

Aphanitic to Porphyritic

Banded, Foliated, Platy

2.2 Color

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

Black, Brown, Pink, Red, White

2.3 Maintenance

Less

2.4 Durability

Durable

2.4.1 Water Resistant

✔ ✘

81% Igneous Rocks Rocks have it !

✔ ✘

81% Metamorphic Rocks Rocks have it !

2.4.2 Scratch Resistant

✔ ✘

86% Igneous Rocks Rocks have it !

✔ ✘

65% Metamorphic Rocks Rocks have it !

2.4.3 Stain Resistant

✔ ✘

66% Igneous Rocks Rocks have it !

✔ ✘

42% Metamorphic Rocks Rocks have it !

2.4.4 Wind Resistant

✔ ✘

49% Igneous Rocks Rocks have it !

✔ ✘

19% Metamorphic Rocks Rocks have it !

2.4.5 Acid Resistant

✔ ✘

48% Igneous Rocks Rocks have it !

✔ ✘

15% Metamorphic Rocks Rocks have it !

2.5 Appearance

Vesicular

Foliated

3 Uses

3.1 Architecture

3.1.1 Interior Uses

Decorative Aggregates, Entryways, Interior Decoration

Countertops, Decorative Aggregates, Flooring, Interior Decoration

3.1.2 Exterior Uses

As Building Stone, Paving Stone, Garden Decoration

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

3.1.3 Other Architectural Uses

Curbing

3.2 Industry

3.2.1 Construction Industry

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

As Dimension Stone

3.2.2 Medical Industry

Not Yet Used

3.3 Antiquity Uses

Artifacts

3.4 Other Uses

3.4.1 Commercial Uses

Commemorative Tablets, Creating Artwork

Cemetery Markers, Jewelry, Tombstones, Used in aquariums

4 Types

4.1 Types

Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite

Augen Gneiss, Henderson Gneiss, Lewisian Gneiss, Archean and Proterozoic Gneiss.

4.2 Features

Host Rock for Lead, Is one of the oldest rock

Generally rough to touch, Is one of the oldest rock

4.3 Archaeological Significance

4.3.1 Monuments

Not Yet Used

Used

4.3.2 Famous Monuments

Not Applicable

Konark Sun Temple in India, Washington Monument, US

4.3.3 Sculpture

Not Yet Used

4.3.4 Famous Sculptures

Not Applicable

4.3.5 Pictographs

Used

Not Used

4.3.6 Petroglyphs

Used

Not Used

4.3.7 Figurines

Not Yet 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.

Gneiss is a high grade metamorphic rock i.e. it has been subjected to higher temperatures and pressures than schist. It is formed by the metamorphosis of Gneiss forms from volcanic rock, shale or granitie.

5.2 Composition

5.2.1 Mineral Content

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

Biotite, Chlorite, Feldspar, Garnet, Graphite, Hornblade, Micas, Muscovite or Illite, Quartz, Quartzite, Silica, Zircon

5.2.2 Compound Content

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

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

5.3 Transformation

5.3.1 Metamorphism

✔ ✘

97% Igneous Rocks Rocks have it !

✔ ✘

50% Metamorphic Rocks Rocks have it !

5.3.2 Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism

Impact Metamorphism

5.3.3 Weathering

✔ ✘

99% Igneous Rocks Rocks have it !

✔ ✘

65% Metamorphic Rocks Rocks have it !

5.3.4 Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Biological Weathering, Mechanical Weathering

5.3.5 Erosion

✔ ✘

92% Igneous Rocks Rocks have it !

✔ ✘

77% Metamorphic Rocks Rocks have it !

5.3.6 Types of Erosion

Chemical Erosion

Chemical Erosion, Coastal Erosion, Sea Erosion

6 Properties

6.1 Physical Properties

6.1.1 Hardness

2-2.25

6.1.2 Grain Size

Medium to Fine Coarse Grained

Medium to Coarse Grained

6.1.3 Fracture

Conchoidal

Irregular

6.1.4 Streak

White

6.1.5 Porosity

Less Porous

Very Less Porous

6.1.6 Luster

Subvitreous to Dull

Dull

6.1.7 Compressive Strength

What Is Flint

⊕

▶

▼

Not Available

Rank: N/A (Overall)▶

125.00 N/mm²

Rank: 17 (Overall)▶

▲

What Is Obsidian

⊕

▶

175 (What Is Grani..)

◀ ▶ ADD ⊕

6.1.8 Cleavage

Perfect

Poor

6.1.9 Toughness

Not Available

1.2

6.1.10 Specific Gravity

2.86-2.87

2.5-2.7

6.1.11 Transparency

Translucent

Translucent to Opaque

6.1.12 Density

2.77-2.771 g/cm³

2.6-2.9 g/cm³

6.2 Thermal Properties

6.2.1 Specific Heat Capacity

What Is Banded ..

⊕

▶

▼

0.92 kJ/Kg K

Rank: 10 (Overall)▶

Not Available

Rank: N/A (Overall)▶

▲

What Is Granulite

⊕

▶

1.09 (What Is Trave..)

◀ ▶ ADD ⊕

6.2.2 Resistance

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Heat Resistant, Pressure Resistant, Scratch Resistant, Wear Resistant

7 Reserves

7.1 Deposits in Eastern Continents

7.1.1 Asia

Not Yet Found

China, India, Iran, Iraq, Kazakhstan, Kyrgyzstan, Mongolia, Russia

7.1.2 Africa

Not Yet Found

Cameroon, Ethiopia, Ghana, Kenya, Madagascar, Morocco, Mozambique, Namibia, Nigeria, Tanzania, Togo

7.1.3 Europe

France, Greece, Romania, Scotland, Spain

Albania, Austria, Bosnia and Herzegovina, Finland, France, Georgia, Germany, Hungary, Italy, Kosovo, Monaco, Norway, Poland, Romania, Serbia, Slovakia, Slovenia, Switzerland, Ukraine, United Kingdom

7.1.4 Others

Not Yet Found

7.2 Deposits in Western Continents

7.2.1 North America

USA

Canada, Costa Rica, Cuba, Mexico, Panama, USA

7.2.2 South America

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

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

7.3 Deposits in Oceania Continent

7.3.1 Australia

New Zealand, South Australia, Western Australia

New South Wales, New Zealand, Queensland, Victoria

All about Dacite and Gneiss Properties

Know all about Dacite and Gneiss properties here. All properties of rocks are important as they define the type of rock and its application. Dacite belongs to Igneous Rocks while Gneiss belongs to Metamorphic Rocks.Texture of Dacite is Aphanitic to Porphyritic whereas that of Gneiss is Banded, Foliated, Platy. Dacite appears Vesicular and Gneiss appears Foliated. The luster of Dacite is subvitreous to dull while that of Gneiss is dull. Dacite is available in bluish - grey, brown, grey, light to dark grey colors whereas Gneiss is available in black, brown, pink, red, white colors. The commercial uses of Dacite are commemorative tablets, creating artwork and that of Gneiss are cemetery markers, jewelry, tombstones, used in aquariums.