Pegmatite

Picrite

Pegmatite and Picrite

Pegmatite

Picrite

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Definition

Pegmatite rock is a holocrystalline, intrusive igneous rock which is composed of interlocking phaneritic crystals

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

History

Origin

Hawaii Islands

Discoverer

R. J. Hauy

Unknown

Etymology

From Greek pegma, pegmat which means- thing joined together + -ite

From Greek pikros bitter + -ite, 19th century

Class

Igneous Rocks

Sub-Class

Durable Rock, Hard Rock

Family

Group

Plutonic

Volcanic

Other Categories

Coarse Grained Rock, Opaque Rock

Fine Grained Rock, Opaque Rock

Texture

Pegmatitic

Earthy, Rough

Color

Black, Brown, Cream, Green, Grey, Pink, Red, Rust, Silver, White, Yellow

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

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Layered, Banded, Veined and Shiny

Rough and Shiny

Uses

Architecture

Interior Uses

Decorative Aggregates, Flooring, Interior Decoration

Countertops, Decorative Aggregates, Homes, Interior Decoration

Exterior Uses

As Building Stone, As Facing Stone, Paving Stone

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

Other Architectural Uses

Curbing

Industry

Construction Industry

As Dimension Stone, Building houses or walls, Construction Aggregate, for Road Aggregate, Landscaping

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, Sculpture, Small Figurines

Artifacts, Monuments, Sculpture

Other Uses

Commercial Uses

Creating Artwork, Jewelry, Source of corundum, tourmalines, beryls and topaz

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

Types

Granite Pegmatite, Gabbro Pegmatite and Diorite Pegmatite

Oceanite

Features

Generally rough to touch, Is one of the oldest rock, Source of corundum, tourmalines, beryls and topaz

Host Rock for Lead

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Formation

Pegmatite rock is holocrystalline, intrusive igneous rock which is formed by partial melting and dewatering during the process of metamorphism.

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

Apatite, Beryl, Feldspar, Fluorite, Garnet, Lepidolite, Quartz, Silica, Spodumene, Topaz

Biotite, Olivine, Plagioclase, Pyrrhotite

Compound Content

Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, Magnesium Carbonate, MgO, Phosphorus Pentoxide

Al, CaO, Carbon Dioxide, Mg, MgO

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional 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

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

Properties

Physical Properties

Hardness

76.8

1 7

👆🏻

Grain Size

Medium to Coarse Grained

Fine Grained

Fracture

Conchoidal

Uneven

Streak

White

White, Greenish White or Grey

Porosity

Less Porous

Luster

Grainy, Pearly and Vitreous

Subvitreous to Dull

Compressive Strength

178.54 N/mm²189.00 N/mm²

0.15 450

👆🏻

Cleavage

Perfect

Toughness

2.1

Specific Gravity

2.6-2.632.75-2.92

0 8.4

👆🏻

Transparency

Translucent to Opaque

Opaque

Density

2.6-2.65 g/cm³1.5-2.5 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.79 kJ/Kg K0.88 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant

Heat Resistant

Reserves

Deposits in Eastern Continents

Asia

China, India, Iran, Japan, Nepal, North Korea, Russia, Saudi Arabia, South Korea

India, Russia

Africa

South Africa

Europe

Austria, France, Greece, Ireland, Italy, Netherlands, Slovakia, Spain, Turkey, Ukraine

Iceland

Others

Deposits in Western Continents

North America

Canada

Canada, USA

South America

Brazil

Deposits in Oceania Continent

Australia

New South Wales, Queensland, South Australia, Western Australia

All about Pegmatite and Picrite Properties

Know all about Pegmatite and Picrite properties here. All properties of rocks are important as they define the type of rock and its application. Pegmatite and Picrite belong to Igneous Rocks.Texture of Pegmatite is Pegmatitic whereas that of Picrite is Earthy, Rough. Pegmatite appears Layered, Banded, Veined and Shiny and Picrite appears Rough and Shiny. The luster of Pegmatite is grainy, pearly and vitreous while that of Picrite is subvitreous to dull. Pegmatite and Picrite are available in black, brown, cream, green, grey, pink, red, rust, silver, white, yellow colors. The commercial uses of Pegmatite are creating artwork, jewelry, source of corundum, tourmalines, beryls and topaz and that of Picrite are as a feed additive for livestock, as armour rock for sea walls, metallurgical flux, pottery, source of magnesia (mgo).