Picrite and Chert

Picrite

Chert

Chert and Picrite

Definition

Picrite is a variety of high-magnesium olivine basalt that is very rich in the mineral olivine

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

History

Origin

Hawaii Islands

Unknown

Discoverer

Unknown

Etymology

From Greek pikros bitter + -ite, 19th century

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, Hard Rock

Family

Group

Volcanic

Not Applicable

Other Categories

Fine Grained Rock, Opaque Rock

Texture

Earthy, Rough

Banded, Rough

Color

Black, Brown, Colourless, Green, Grey, Pink, White, Yellow

Black, Brown, Green, Grey, Red, White

Maintenance

Less

Durability

Durable

Water Resistant

Yes

Scratch Resistant

Yes

Stain Resistant

Yes

Wind Resistant

Yes

Acid Resistant

Yes

Appearance

Rough and Shiny

Glassy or Pearly

Uses

Architecture

Interior Uses

Countertops, Decorative Aggregates, Homes, Interior Decoration

Decorative Aggregates, Homes

Exterior Uses

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

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

Other Architectural Uses

Curbing

Industry

Construction Industry

As a Sintering Agent in Steel Industry to process Iron Ore, Cement Manufacture, for Road Aggregate, Manufacture of Magnesium and Dolomite Refractories, Roadstone, Used for flooring, stair treads, borders and window sills.

Arrowheads, Construction Aggregate, Cutting Tool, Spear Points

Medical Industry

Not Yet Used

Antiquity Uses

Artifacts, Monuments, Sculpture

Artifacts, Monuments

Other Uses

Commercial Uses

As a Feed Additive for Livestock, As armour rock for sea walls, Metallurgical Flux, Pottery, Source of Magnesia (MgO)

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

Types

Oceanite

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

Features

Host Rock for Lead

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

Archaeological Significance

Monuments

Used

Famous Monuments

Data Not Available

Sculpture

Used

Not Yet Used

Famous Sculptures

Data Not Available

Not Applicable

Pictographs

Not Used

Petroglyphs

Not Used

Figurines

Used

Not Yet Used

Fossils

Absent

Present

Formation

Picrite 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.

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

Biotite, Olivine, Plagioclase, Pyrrhotite

Quartz, Silicon

Compound Content

Al, CaO, Carbon Dioxide, Mg, MgO

Silicon Dioxide

Transformation

Metamorphism

Yes

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Impact Metamorphism, Regional Metamorphism

Not Applicable

Weathering

Yes

Types of Weathering

Biological Weathering

Not Applicable

Erosion

Yes

Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion

Chemical Erosion

Properties

Physical Properties

Hardness

6.8

6.5-7

Grain Size

Fine Grained

Very fine-grained

Fracture

Uneven

Uneven, Splintery or Conchoidal

Streak

White, Greenish White or Grey

White

Porosity

Less Porous

Highly Porous

Luster

Subvitreous to Dull

Waxy and Dull

Compressive Strength

189.00 N/mm²

450.00 N/mm²

Cleavage

Imperfect

Non-Existent

Toughness

2.1

1.5

Specific Gravity

2.75-2.92

2.5-2.8

Transparency

Opaque

Translucent to Opaque

Density

1.5-2.5 g/cm³

2.7 g/cm³

Thermal Properties

Specific Heat Capacity

0.88 kJ/Kg K

0.74 kJ/Kg K

Resistance

Heat 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

South Africa

Kenya, Morocco, South Africa, Tanzania

Europe

Iceland

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

Others

Not Yet Found

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

Not Yet Found

New South Wales, Queensland, South Australia, Western Australia

Summary >>

<< Reserves

All about Picrite and Chert Properties

Know all about Picrite and Chert properties here. All properties of rocks are important as they define the type of rock and its application. Picrite belongs to Igneous Rocks while Chert belongs to Sedimentary Rocks.Texture of Picrite is Earthy, Rough whereas that of Chert is Banded, Rough. Picrite appears Rough and Shiny and Chert appears Glassy or Pearly. The luster of Picrite is subvitreous to dull while that of Chert is waxy and dull. Picrite is available in black, brown, colourless, green, grey, pink, white, yellow colors whereas Chert is available in black, brown, green, grey, red, white colors. The commercial uses of Picrite are as a feed additive for livestock, as armour rock for sea walls, metallurgical flux, pottery, source of magnesia (mgo) and that of Chert are creating artwork, gemstone, in fire-starting tools, jewelry, to ignite fire, used in flintlock firearms.