Dacite

Chert

Dacite and Chert

Dacite

Chert

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1 Definition

1.1 Definition

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

Chert is a hard, dark, opaque sedimentary rock which is composed of silica with an amorphous fine-grained texture

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 flint-like quartz, 1670s, of unknown origin- a local term, which has been taken into geological use

1.4 Class

Igneous Rocks

Sedimentary 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

Fine Grained Rock, Opaque Rock

2 Texture

2.1 Texture

Aphanitic to Porphyritic

Banded, Rough

2.2 Color

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

Black, Brown, Green, Grey, Red, 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

Glassy or Pearly

3 Uses

3.1 Architecture

3.1.1 Interior Uses

Decorative Aggregates, Entryways, Interior Decoration

Decorative Aggregates, Homes

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

Arrowheads, Construction Aggregate, Cutting Tool, Spear Points

3.2.2 Medical Industry

Not Yet Used

3.3 Antiquity Uses

Artifacts

Artifacts, Monuments

3.4 Other Uses

3.4.1 Commercial Uses

Commemorative Tablets, Creating Artwork

Creating Artwork, Gemstone, In fire-starting tools, Jewelry, To ignite fire, Used in flintlock firearms

4 Types

4.1 Types

Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite

Flint, Jasper, Radiolarite, Common Chert, Chalcedony, Agate, Onyx, Opal, Magadi-type Chert, Porcelanite, Siliceous Sinter

4.2 Features

Host Rock for Lead, Is one of the oldest rock

Clasts are smooth to touch, Easily splits into thin plates, Has High structural resistance against erosion and climate

4.3 Archaeological Significance

4.3.1 Monuments

Not Yet Used

Used

4.3.2 Famous Monuments

Not Applicable

Data Not Available

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

Present

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.

Chert forms when microcrystals of silicon dioxide grow within soft sediments that become limestone or chalk. The chert formation can be either of chemical or biological origin.

5.2 Composition

5.2.1 Mineral Content

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

Quartz, Silicon

5.2.2 Compound Content

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

Silicon Dioxide

5.3 Transformation

5.3.1 Metamorphism

✔ ✘

5.3.2 Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism

Not Applicable

5.3.3 Weathering

✔ ✘

5.3.4 Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Not Applicable

5.3.5 Erosion

✔ ✘

5.3.6 Types of Erosion

Chemical Erosion

6 Properties

6.1 Physical Properties

6.1.1 Hardness

2-2.256.5-7

1 7

6.1.2 Grain Size

Medium to Fine Coarse Grained

Very fine-grained

6.1.3 Fracture

Conchoidal

Uneven, Splintery or Conchoidal

6.1.4 Streak

White

6.1.5 Porosity

Less Porous

Highly Porous

6.1.6 Luster

Subvitreous to Dull

Waxy and Dull

6.1.7 Compressive Strength

NA450.00 N/mm²

0.15 450

6.1.8 Cleavage

Perfect

Non-Existent

6.1.9 Toughness

Not Available

1.5

6.1.10 Specific Gravity

2.86-2.872.5-2.8

0 8.4

6.1.11 Transparency

Translucent

Translucent to Opaque

6.1.12 Density

2.77-2.771 g/cm³2.7 g/cm³

0 1400

6.2 Thermal Properties

6.2.1 Specific Heat Capacity

0.92 kJ/Kg K0.74 kJ/Kg K

0.14 3.2

6.2.2 Resistance

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

7 Reserves

7.1 Deposits in Eastern Continents

7.1.1 Asia

Not Yet Found

China, India, Iran, Japan, Oman, Russia, Saudi Arabia, Taiwan, Thailand, Vietnam

7.1.2 Africa

Not Yet Found

Kenya, Morocco, South Africa, Tanzania

7.1.3 Europe

France, Greece, Romania, Scotland, Spain

Austria, France, Greece, Italy, Malta, Poland, Portugal, Serbia, Spain, Sweden, United Kingdom

7.1.4 Others

Not Yet Found

Greenland, Mid-Atlantic Ridge

7.2 Deposits in Western Continents

7.2.1 North America

USA

Canada, Mexico, USA

7.2.2 South America

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

Bolivia, Brazil

7.3 Deposits in Oceania Continent

7.3.1 Australia

New Zealand, South Australia, Western Australia

New South Wales, Queensland, South Australia, Western Australia

All about Dacite and Chert Properties

Know all about Dacite and Chert properties here. All properties of rocks are important as they define the type of rock and its application. Dacite belongs to Igneous Rocks while Chert belongs to Sedimentary Rocks.Texture of Dacite is Aphanitic to Porphyritic whereas that of Chert is Banded, Rough. Dacite appears Vesicular and Chert appears Glassy or Pearly. The luster of Dacite is subvitreous to dull while that of Chert is waxy and dull. Dacite is available in bluish - grey, brown, grey, light to dark grey colors whereas Chert is available in black, brown, green, grey, red, white colors. The commercial uses of Dacite are commemorative tablets, creating artwork and that of Chert are creating artwork, gemstone, in fire-starting tools, jewelry, to ignite fire, used in flintlock firearms.