Adakite

Chert

Adakite and Chert

Adakite

Chert

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Definition

Adakite is an intermediate to felsic volcanic rock that has geochemical characteristics of magma which is said to be formed by partial melting of altered basalt that is subducted below volcanic arcs

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

History

Origin

Adak, Aleutian Islands

Discoverer

Defant and Drummond

Unknown

Etymology

From Adak, Aleutian Islands

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

Class

Igneous Rocks

Sedimentary Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Durable Rock, Hard Rock

Family

Group

Volcanic

Other Categories

Fine Grained Rock, Medium Grained Rock, Opaque Rock

Fine Grained Rock, Opaque Rock

Texture

Porphyritic

Banded, Rough

Color

Black, Brown, Light to Dark Grey

Black, Brown, Green, Grey, Red, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull and Soft

Glassy or Pearly

Uses

Architecture

Interior Uses

Decorative Aggregates, Floor Tiles, Homes, Hotels, Kitchens

Decorative Aggregates, Homes

Exterior Uses

As Building Stone, As Facing Stone, Office Buildings

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

Other Architectural Uses

Whetstones

Curbing

Industry

Construction Industry

As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone

Arrowheads, Construction Aggregate, Cutting Tool, Spear Points

Medical Industry

Antiquity Uses

Monuments, Sculpture, Small Figurines

Artifacts, Monuments

Other Uses

Commercial Uses

Commemorative Tablets, Pottery, Used in aquariums

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

Types

Intermediate volcanic rock

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

Features

Has High structural resistance against erosion and climate, Host rock for Diamond, Very fine grained rock

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

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Present

Formation

Adakite rocks are formed when the hydrous fluids are released from minerals that break down in metamorphosed basalt, and rise into the mantle they initiate partial melting.

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.

Composition

Mineral Content

Olivine, Plagioclase, Pyroxene

Quartz, Silicon

Compound Content

Aluminium Oxide, MgO, Silicon Dioxide

Silicon Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Coastal Erosion, Sea Erosion, Water Erosion

Chemical Erosion

Properties

Physical Properties

Hardness

3-46.5-7

1 7

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Grain Size

Fine to Medium Grained

Very fine-grained

Fracture

Conchoidal

Uneven, Splintery or Conchoidal

Streak

Bluish Black

White

Porosity

Less Porous

Highly Porous

Luster

Grainy, Pearly and Vitreous

Waxy and Dull

Compressive Strength

200.00 N/mm²450.00 N/mm²

0.15 450

👆🏻

Cleavage

Toughness

1.5

Specific Gravity

-99992.5-2.8

0 8.4

👆🏻

Transparency

Opaque

Translucent to Opaque

Density

-9999 g/cm³2.7 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.84 kJ/Kg K0.74 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Pressure Resistant, Wear Resistant

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

India, Russia

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

Africa

Ethiopia, Somalia, South Africa

Kenya, Morocco, South Africa, Tanzania

Europe

Iceland

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

Others

Greenland, Mid-Atlantic Ridge

Deposits in Western Continents

North America

Canada, USA

Canada, Mexico, USA

South America

Brazil

Bolivia, Brazil

Deposits in Oceania Continent

Australia

New South Wales, Queensland, South Australia, Western Australia

All about Adakite and Chert Properties

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