Picrite

Obsidian

Picrite and Obsidian

Picrite

Obsidian

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1 Definition

1.1 Definition

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

Obsidian is a naturally occurring volcanic glass formed as an extrusive igneous rock. It is produced when felsic lava extruded from a volcano cools rapidly with minimum crystal growth

1.2 History

1.2.1 Origin

Hawaii Islands

Ethiopia

1.2.2 Discoverer

Unknown

Obsius

1.3 Etymology

From Greek pikros bitter + -ite, 19th century

From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius

1.4 Class

Igneous Rocks

1.4.1 Sub-Class

Durable Rock, Hard Rock

Durable Rock, Medium Hardness Rock

1.5 Family

1.5.1 Group

Volcanic

1.6 Other Categories

Fine Grained Rock, Opaque Rock

Opaque Rock

2 Texture

2.1 Texture

Earthy, Rough

Glassy

2.2 Color

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

Black, Blue, Brown, Green, Orange, Red, Tan, Yellow

2.3 Maintenance

Less

2.4 Durability

Durable

2.4.1 Water Resistant

✔ ✘

2.4.2 Scratch Resistant

✔ ✘

2.4.3 Stain Resistant

✔ ✘

2.4.4 Wind Resistant

✔ ✘

2.4.5 Acid Resistant

✔ ✘

2.5 Appearance

Rough and Shiny

Shiny

3 Uses

3.1 Architecture

3.1.1 Interior Uses

Countertops, Decorative Aggregates, Homes, Interior Decoration

Decorative Aggregates, Interior Decoration

3.1.2 Exterior Uses

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

Garden Decoration

3.1.3 Other Architectural Uses

Curbing

Not Yet Used

3.2 Industry

3.2.1 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, Cutting Tool, Knives, Scrapers, Spear Points

3.2.2 Medical Industry

Not Yet Used

Surgery

3.3 Antiquity Uses

Artifacts, Monuments, Sculpture

Artifacts, Jewellery

3.4 Other Uses

3.4.1 Commercial Uses

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

Creating Artwork, Mirror, Used in aquariums

4 Types

4.1 Types

Oceanite

Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian

4.2 Features

Host Rock for Lead

Blocks negativity, Helps to protect against depression

4.3 Archaeological Significance

4.3.1 Monuments

Used

Not Yet Used

4.3.2 Famous Monuments

Data Not Available

Not Applicable

4.3.3 Sculpture

Used

Not Yet Used

4.3.4 Famous Sculptures

Data Not Available

Not Applicable

4.3.5 Pictographs

Not Used

Used

4.3.6 Petroglyphs

Not Used

Used

4.3.7 Figurines

Used

Not Yet Used

4.4 Fossils

Absent

5 Formation

5.1 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.

When the lava is released from volcano, it undergoes a very rapid cooling which freezes the mechanisms of crystallization. The result is a volcanic glass with a uniform smooth texture.

5.2 Composition

5.2.1 Mineral Content

Biotite, Olivine, Plagioclase, Pyrrhotite

Not Available

5.2.2 Compound Content

Al, CaO, Carbon Dioxide, Mg, MgO

Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide

5.3 Transformation

5.3.1 Metamorphism

✔ ✘

5.3.2 Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Impact Metamorphism, Regional Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism

5.3.3 Weathering

✔ ✘

5.3.4 Types of Weathering

Biological Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

5.3.5 Erosion

✔ ✘

5.3.6 Types of Erosion

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

Chemical Erosion, Coastal Erosion, Glacier Erosion

6 Properties

6.1 Physical Properties

6.1.1 Hardness

6.85-5.5

1 7

6.1.2 Grain Size

Fine Grained

Not Applicable

6.1.3 Fracture

Uneven

Conchoidal

6.1.4 Streak

White, Greenish White or Grey

White

6.1.5 Porosity

Less Porous

Very Less Porous

6.1.6 Luster

Subvitreous to Dull

Vitreous

6.1.7 Compressive Strength

189.00 N/mm²0.15 N/mm²

0.15 450

6.1.8 Cleavage

Imperfect

Non-Existent

6.1.9 Toughness

2.1

Not Available

6.1.10 Specific Gravity

2.75-2.922.6-2.7

0 8.4

6.1.11 Transparency

Opaque

Translucent

6.1.12 Density

1.5-2.5 g/cm³2.6 g/cm³

0 1400

6.2 Thermal Properties

6.2.1 Specific Heat Capacity

0.88 kJ/Kg K0.92 kJ/Kg K

0.14 3.2

6.2.2 Resistance

Heat Resistant

Heat Resistant, Impact Resistant

7 Reserves

7.1 Deposits in Eastern Continents

7.1.1 Asia

India, Russia

Afghanistan, Indonesia, Japan, Russia

7.1.2 Africa

South Africa

Kenya

7.1.3 Europe

Iceland

Greece, Hungary, Iceland, Italy, Turkey

7.1.4 Others

Not Yet Found

7.2 Deposits in Western Continents

7.2.1 North America

Canada, USA

Canada, Mexico, USA

7.2.2 South America

Brazil

Argentina, Chile, Ecuador, Peru

7.3 Deposits in Oceania Continent

7.3.1 Australia

Not Yet Found

New Zealand

All about Picrite and Obsidian Properties

Know all about Picrite and Obsidian properties here. All properties of rocks are important as they define the type of rock and its application. Picrite and Obsidian belong to Igneous Rocks.Texture of Picrite is Earthy, Rough whereas that of Obsidian is Glassy. Picrite appears Rough and Shiny and Obsidian appears Shiny. The luster of Picrite is subvitreous to dull while that of Obsidian is vitreous. Picrite is available in black, brown, colourless, green, grey, pink, white, yellow colors whereas Obsidian is available in black, blue, brown, green, orange, red, tan, yellow 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 Obsidian are creating artwork, mirror, used in aquariums.