Chert

Scoria

Chert and Scoria

Chert

Scoria

Add ⊕

Definition

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

Scoria is a dark-colored extrusive igneous rock with abundant round bubble-like cavities

History

Origin

Discoverer

Unknown

Etymology

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

From late Middle English (denoting slag from molten metal), from Greek skōria refuse, from skōr dung

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

Vesicular

Color

Black, Brown, Green, Grey, Red, White

Black, Brown, Dark Grey to Black, Red

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Glassy or Pearly

Glassy and Vesicular

Uses

Architecture

Interior Uses

Decorative Aggregates, Homes

Decorative Aggregates, Interior Decoration

Exterior Uses

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

Garden Decoration, Paving Stone

Other Architectural Uses

Curbing

Industry

Construction Industry

Arrowheads, Construction Aggregate, Cutting Tool, Spear Points

Cement Manufacture, Construction Aggregate, for Road Aggregate, In landscaping and drainage works

Medical Industry

Antiquity Uses

Artifacts, Monuments

Artifacts, Monuments, Sculpture

Other Uses

Commercial Uses

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

As a traction material on snow-covered roads, Creating Artwork, High-temperature insulation, In gas barbecue grills

Types

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

Basaltic Scoria and Andesitic Scoria

Features

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

Available in Lots of Colors and Patterns, Generally rough to touch, Surfaces are often shiny

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.

Scoria forms when magma containing huge amount of dissolved gas flows from a volcano during an eruption.

Composition

Mineral Content

Quartz, Silicon

Apatite, Biotite, Calcite, Feldspar, Hematite, Hornblade, Ilmenite, Magnetite, Olivine, Pyroxene, Quartz, Silica

Compound Content

Silicon Dioxide

Ca, NaCl

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Properties

Physical Properties

Hardness

6.5-75-6

1 7

👆🏻

Grain Size

Very fine-grained

Fine Grained

Fracture

Uneven, Splintery or Conchoidal

Conchoidal

Streak

White

Porosity

Highly Porous

Luster

Waxy and Dull

Subvitreous to Dull

Compressive Strength

450.00 N/mm²70.00 N/mm²

0.15 450

👆🏻

Cleavage

Perfect

Toughness

1.5

2.1

Specific Gravity

2.5-2.8-9999

0 8.4

👆🏻

Transparency

Translucent to Opaque

Opaque

Density

2.7 g/cm³-9999 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

Reserves

Deposits in Eastern Continents

Asia

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

Afghanistan, Indonesia, Japan, Russia

Africa

Kenya, Morocco, South Africa, Tanzania

Ethiopia, Kenya, Tanzania

Europe

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

Greece, Hungary, Iceland, Italy, Turkey

Others

Greenland, Mid-Atlantic Ridge

Deposits in Western Continents

North America

Canada, Mexico, USA

Bahamas, Barbados, Canada, Costa Rica, Cuba, Jamaica, Mexico, USA

South America

Bolivia, Brazil

Argentina, Chile, Ecuador, Peru

Deposits in Oceania Continent

Australia

New South Wales, Queensland, South Australia, Western Australia

New Zealand, Western Australia

All about Chert and Scoria Properties

Know all about Chert and Scoria properties here. All properties of rocks are important as they define the type of rock and its application. Chert belongs to Sedimentary Rocks while Scoria belongs to Igneous Rocks.Texture of Chert is Banded, Rough whereas that of Scoria is Vesicular. Chert appears Glassy or Pearly and Scoria appears Glassy and Vesicular. The luster of Chert is waxy and dull while that of Scoria is subvitreous to dull. Chert is available in black, brown, green, grey, red, white colors whereas Scoria is available in black, brown, dark grey to black, red 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 Scoria are as a traction material on snow-covered roads, creating artwork, high-temperature insulation, in gas barbecue grills.