Websterite

Obsidian

Websterite and Obsidian

Websterite

Obsidian

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Definition

Websterite is ultramafic and ultrabasic rock that consists of roughly equal proportions of orthopyroxene and clinopyroxene. It is a special type of pyroxenite.

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

History

Origin

Webster, North Carolina

Ethiopia

Discoverer

Unknown

Obsius

Etymology

From the town of Webster located in North Carolina

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

Class

Igneous Rocks

Sub-Class

Durable Rock, Hard Rock

Durable Rock, Medium Hardness Rock

Family

Group

Plutonic

Volcanic

Other Categories

Coarse Grained Rock, Opaque Rock

Opaque Rock

Texture

Clastic, Granular, Phaneritic, Porphyritic

Glassy

Color

Black to Grey, Bluish - Grey, Dark Greenish - Grey, Green, Light Greenish Grey

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

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Layered, Banded, Veined and Shiny

Shiny

Uses

Architecture

Interior Uses

Countertops, Decorative Aggregates, Entryways, Floor Tiles, Flooring, Interior Decoration

Decorative Aggregates, Interior Decoration

Exterior Uses

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

Garden Decoration

Other Architectural Uses

Curbing

Industry

Construction Industry

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

Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points

Medical Industry

Surgery

Antiquity Uses

Artifacts

Artifacts, Jewellery

Other Uses

Commercial Uses

Cemetery Markers, Commemorative Tablets, Creating Artwork, Laboratory bench tops, Jewelry, Sea Defence, Tombstones

Creating Artwork, Mirror, Used in aquariums

Types

Ultramafic rock

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

Features

Generally rough to touch, Is one of the oldest rock

Blocks negativity, Helps to protect against depression

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Formation

Websterite can be formed as cumulates in ultramafic intrusions by accumulation of pyroxene crystals at the base of the lava chamber.

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.

Composition

Mineral Content

Amphibole, Augite, Bronzite, Chromite, Diopside, Enstatite, Garnet, Hornblende, Hypersthene, Magnetite, Pyroxene

Compound Content

Aluminium Oxide, CaO, Chromium(III) Oxide, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Sulfur Trioxide

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

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Impact Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

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

Chemical Erosion, Coastal Erosion, Glacier Erosion

Properties

Physical Properties

Hardness

75-5.5

1 7

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Grain Size

Coarse Grained

Fracture

Uneven

Conchoidal

Streak

White, Greenish White or Grey

White

Porosity

Less Porous

Very Less Porous

Luster

Dull to Vitreous to Submetallic

Vitreous

Compressive Strength

95.00 N/mm²0.15 N/mm²

0.15 450

👆🏻

Cleavage

Toughness

Specific Gravity

3.2-3.52.6-2.7

0 8.4

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Transparency

Opaque

Translucent

Density

3.1-3.6 g/cm³2.6 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.79 kJ/Kg K0.92 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Impact Resistant, Pressure Resistant, Wear Resistant

Heat Resistant, Impact Resistant

Reserves

Deposits in Eastern Continents

Asia

India, Russia

Afghanistan, Indonesia, Japan, Russia

Africa

South Africa

Kenya

Europe

Germany, Greece, Italy, Scotland, Turkey

Greece, Hungary, Iceland, Italy, Turkey

Others

Greenland

Deposits in Western Continents

North America

Canada, USA

Canada, Mexico, USA

South America

Brazil, Colombia, Venezuela

Argentina, Chile, Ecuador, Peru

Deposits in Oceania Continent

Australia

New Zealand, Queensland

New Zealand

All about Websterite and Obsidian Properties

Know all about Websterite and Obsidian properties here. All properties of rocks are important as they define the type of rock and its application. Websterite and Obsidian belong to Igneous Rocks.Texture of Websterite is Clastic, Granular, Phaneritic, Porphyritic whereas that of Obsidian is Glassy. Websterite appears Layered, Banded, Veined and Shiny and Obsidian appears Shiny. The luster of Websterite is dull to vitreous to submetallic while that of Obsidian is vitreous. Websterite is available in black to grey, bluish - grey, dark greenish - grey, green, light greenish grey colors whereas Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors. The commercial uses of Websterite are cemetery markers, commemorative tablets, creating artwork, laboratory bench tops, jewelry, sea defence, tombstones and that of Obsidian are creating artwork, mirror, used in aquariums.