Dunite

Picrite

Dunite and Picrite

Dunite

Picrite

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Definition

Dunite is a green to brownish coarse-grained igneous rock mainly consisting of olivine

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

History

Origin

New Zealand

Hawaii Islands

Discoverer

Ferdinand von Hochstetter

Unknown

Etymology

From the name of Dun Mountain, New Zealand, + -ite1

From Greek pikros bitter + -ite, 19th century

Class

Igneous Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Durable Rock, Hard Rock

Family

Group

Plutonic

Volcanic

Other Categories

Coarse Grained Rock, Opaque Rock

Fine Grained Rock, Opaque Rock

Texture

Phaneritic

Earthy, Rough

Color

Dark Greenish - Grey

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

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Rough and Shiny

Uses

Architecture

Interior Uses

Decorative Aggregates, Interior Decoration

Countertops, Decorative Aggregates, Homes, Interior Decoration

Exterior Uses

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

Other Architectural Uses

Curbing

Industry

Construction Industry

As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate, Making natural cement, Raw material for the manufacture of mortar

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.

Medical Industry

Antiquity Uses

Artifacts, Monuments, Sculpture, Small Figurines

Artifacts, Monuments, Sculpture

Other Uses

Commercial Uses

Creating Artwork, Gemstone, Jewelry, Source of Chromite, Platinum, Nickel and Garnet, Source of Diamonds

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

Types

Dunite

Oceanite

Features

Constitutes upper part of the Earth's mantle, Generally rough to touch, Host rock for Diamond, Is one of the oldest rock

Host Rock for Lead

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Formation

Dunite is a plutonic ultramafic igneous rock consisting almost m olivine. It can be formed in two ways.

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.

Composition

Mineral Content

Amphibole, Chromite, Garnet, Magnesium, Olivine, Phlogopite, Plagioclase, Pyroxene

Biotite, Olivine, Plagioclase, Pyrrhotite

Compound Content

Ca, CaO, Fe, Potassium, Silicon Dioxide, Sodium, Titanium Dioxide

Al, CaO, Carbon Dioxide, Mg, MgO

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Impact Metamorphism, Regional Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Biological Weathering

Erosion

✔ ✘

Types of Erosion

Coastal Erosion, Glacier Erosion, Water Erosion

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

Properties

Physical Properties

Hardness

3.5-46.8

1 7

👆🏻

Grain Size

Coarse Grained

Fine Grained

Fracture

Irregular

Uneven

Streak

White

White, Greenish White or Grey

Porosity

Less Porous

Luster

Shiny

Subvitreous to Dull

Compressive Strength

107.55 N/mm²189.00 N/mm²

0.15 450

👆🏻

Cleavage

Toughness

2.1

Specific Gravity

3-3.012.75-2.92

0 8.4

👆🏻

Transparency

Translucent to Opaque

Opaque

Density

2.84-2.85 g/cm³1.5-2.5 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

1.25 kJ/Kg K0.88 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Pressure Resistant, Wear Resistant

Heat Resistant

Reserves

Deposits in Eastern Continents

Asia

China, India, Indonesia, Kazakhstan, Russia, South Korea, Thailand, Turkey

India, Russia

Africa

Morocco, South Africa

South Africa

Europe

Finland, France, Georgia, Germany, Great Britain, Italy, Kazakhstan, Netherlands, Norway, Spain, Switzerland

Iceland

Others

Deposits in Western Continents

North America

Canada, USA

South America

Argentina, Brazil, Colombia, Ecuador, Venezuela

Brazil

Deposits in Oceania Continent

Australia

New Zealand, Western Australia

All about Dunite and Picrite Properties

Know all about Dunite and Picrite properties here. All properties of rocks are important as they define the type of rock and its application. Dunite and Picrite belong to Igneous Rocks.Texture of Dunite is Phaneritic whereas that of Picrite is Earthy, Rough. Dunite appears Rough and Shiny and Picrite appears Rough and Shiny. The luster of Dunite is shiny while that of Picrite is subvitreous to dull. Dunite is available in dark greenish - grey colors whereas Picrite is available in black, brown, green, grey, pink, white, yellow colors. The commercial uses of Dunite are creating artwork, gemstone, jewelry, source of chromite, platinum, nickel and garnet, source of diamonds and that of Picrite are as a feed additive for livestock, as armour rock for sea walls, metallurgical flux, pottery, source of magnesia (mgo).