Slate

Picrite

Slate and Picrite

Slate

Picrite

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Definition

Slate is a fine-grained, foliated, homogeneous metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade regional metamorphism

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

History

Origin

England

Hawaii Islands

Discoverer

Abraham Gottlob Werner

Unknown

Etymology

From Old French esclate, from esclat (French éclat)

From Greek pikros bitter + -ite, 19th century

Class

Metamorphic Rocks

Igneous Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Durable Rock, Hard Rock

Family

Group

Volcanic

Other Categories

Fine Grained Rock, Opaque Rock

Texture

Foliated

Earthy, Rough

Color

Black, Brown, Buff, Green, Light to Dark Grey, Purple, Red, Shades of Blue

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

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Dull

Rough and Shiny

Uses

Architecture

Interior Uses

Bathrooms, Decorative Aggregates, Entryways, Floor Tiles, Flooring, Homes, Hotels, Interior Decoration, Kitchens, Stair Treads

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

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

Blackboards, Commemorative Tablets, Laboratory bench tops, Standard material for the bed of Billiard table, Standard material for the beds of Pool and Snooker table, Tombstones, Used in aquariums, Writing Slates

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

Types

Phyllite, Schist, and Slate

Oceanite

Features

Easily splits into thin plates, Surfaces are often shiny, Very fine grained rock

Host Rock for Lead

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Formation

Slate is a low grade metamorphic rock that is generally formed by metamorphosis of mudstone or shale, under relatively low pressure and temperature conditions.

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, Biotite, Chlorite, Feldspar, Graphite, Hematite, Kaolinite, Magnetite, Pyrite, Tourmaline, Zircon

Biotite, Olivine, Plagioclase, Pyrrhotite

Compound Content

Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Titanium Dioxide

Al, CaO, Carbon Dioxide, Mg, MgO

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic 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

Coastal Erosion, Glacier Erosion, Water Erosion, Wind Erosion

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

Properties

Physical Properties

Hardness

3-46.8

1 7

👆🏻

Grain Size

Very fine-grained

Fine Grained

Fracture

Splintery

Uneven

Streak

Light to dark brown

White, Greenish White or Grey

Porosity

Less Porous

Luster

Dull

Subvitreous to Dull

Compressive Strength

30.00 N/mm²189.00 N/mm²

0.15 450

👆🏻

Cleavage

Slaty

Toughness

1.2

2.1

Specific Gravity

2.65-2.82.75-2.92

0 8.4

👆🏻

Transparency

Opaque

Density

2.6-2.8 g/cm³1.5-2.5 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.76 kJ/Kg K0.88 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Heat Resistant

Reserves

Deposits in Eastern Continents

Asia

China, India, Turkey

India, Russia

Africa

South Africa

Europe

Belgium, France, Germany, Italy, Norway, Portugal, Spain, United Kingdom

Iceland

Others

Arctic

Deposits in Western Continents

North America

USA

Canada, USA

South America

Brazil

Deposits in Oceania Continent

Australia

All about Slate and Picrite Properties

Know all about Slate and Picrite properties here. All properties of rocks are important as they define the type of rock and its application. Slate belongs to Metamorphic Rocks while Picrite belongs to Igneous Rocks.Texture of Slate is Foliated whereas that of Picrite is Earthy, Rough. Slate appears Dull and Picrite appears Rough and Shiny. The luster of Slate is dull while that of Picrite is subvitreous to dull. Slate is available in black, brown, buff, green, light to dark grey, purple, red, shades of blue colors whereas Picrite is available in black, brown, green, grey, pink, white, yellow colors. The commercial uses of Slate are blackboards, commemorative tablets, laboratory bench tops, standard material for the bed of billiard table, standard material for the beds of pool and snooker table, tombstones, used in aquariums, writing slates and that of Picrite are as a feed additive for livestock, as armour rock for sea walls, metallurgical flux, pottery, source of magnesia (mgo).