Chert

Trachyandesite

Chert and Trachyandesite

Chert

Trachyandesite

Add ⊕

Definition

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

Trachyandesite is an extrusive igneous rock.

History

Origin

Indonesia

Discoverer

Unknown

Etymology

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

From French trachyandésite, trachy + andésite andesite, a lava intermediate in composition between trachyte and andesite

Class

Sedimentary Rocks

Igneous Rocks

Sub-Class

Durable Rock, Hard Rock

Durable Rock, Medium Hardness Rock

Family

Group

Volcanic

Other Categories

Fine Grained Rock, Opaque Rock

Texture

Banded, Rough

Glassy, Massive, Porphyritic, Scoriaceous, Vesicular

Color

Black, Brown, Green, Grey, Red, White

Black, Brown, Light to Dark Grey

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Glassy or Pearly

Dull and Soft

Uses

Architecture

Interior Uses

Decorative Aggregates, Homes

Countertops, Decorative Aggregates, Homes, Interior Decoration

Exterior Uses

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

As Building Stone, As Facing Stone, Garden Decoration

Other Architectural Uses

Curbing

Industry

Construction Industry

Arrowheads, Construction Aggregate, Cutting Tool, Spear Points

Building houses or walls, Cobblestones, for Road Aggregate, Rail Track Ballast, Roadstone

Medical Industry

Antiquity Uses

Artifacts, Monuments

Artifacts, Sculpture

Other Uses

Commercial Uses

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

Creating Artwork, Pottery

Types

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

Basaltic Trachyandesite

Features

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

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

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Present

Absent

Formation

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.

Trachyandesite 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.

Composition

Mineral Content

Quartz, Silicon

Alkali feldspar, Biotite, Olivine, Plagioclase, Pyroxene, Sodic plagioclase

Compound Content

Silicon Dioxide

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

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Cataclastic Metamorphism, Contact Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion

Chemical Erosion, Coastal Erosion, Water Erosion, Wind Erosion

Properties

Physical Properties

Hardness

6.5-74-5

1 7

👆🏻

Grain Size

Very fine-grained

Fine Grained

Fracture

Uneven, Splintery or Conchoidal

Conchoidal

Streak

White

Light to dark brown

Porosity

Highly Porous

Less Porous

Luster

Waxy and Dull

Earthy

Compressive Strength

450.00 N/mm²37.40 N/mm²

0.15 450

👆🏻

Cleavage

Perfect

Toughness

1.5

2.3

Specific Gravity

2.5-2.82.8-3

0 8.4

👆🏻

Transparency

Translucent to Opaque

Opaque

Density

2.7 g/cm³2.9-3.1 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.74 kJ/Kg K0.84 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Heat Resistant, Pressure Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

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

India, Russia

Africa

Kenya, Morocco, South Africa, Tanzania

South Africa

Europe

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

Iceland

Others

Greenland, Mid-Atlantic Ridge

Deposits in Western Continents

North America

Canada, Mexico, USA

Canada, USA

South America

Bolivia, Brazil

Brazil

Deposits in Oceania Continent

Australia

New South Wales, Queensland, South Australia, Western Australia

All about Chert and Trachyandesite Properties

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