Obsidian

Marl

Obsidian and Marl

Obsidian

Marl

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Definition

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

Marl is an unconsolidated sedimentary rock consisting of clay and lime

History

Origin

Ethiopia

Discoverer

Obsius

William Smith

Etymology

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

From Old French marle, from Late Latin marglia

Class

Igneous Rocks

Sedimentary Rocks

Sub-Class

Durable Rock, Medium Hardness Rock

Durable Rock, Soft Rock

Family

Group

Volcanic

Other Categories

Opaque Rock

Fine Grained Rock, Opaque Rock

Texture

Glassy

Earthy

Color

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

Beige, Brown, Green, Grey, White

Maintenance

Less

Durability

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Shiny

Rough and Dull

Uses

Architecture

Interior Uses

Decorative Aggregates, Interior Decoration

Decorative Aggregates, Floor Tiles

Exterior Uses

Garden Decoration

As Building Stone, Roof Tiles

Other Architectural Uses

Curbing

Industry

Construction Industry

Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points

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

Medical Industry

Surgery

Antiquity Uses

Artifacts, Jewellery

Artifacts, Jewellery, Sculpture, Small Figurines

Other Uses

Commercial Uses

Creating Artwork, Mirror, Used in aquariums

Creating Artwork, Soil Conditioner

Types

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

Clay Marl ,Blue Marl, Red Marl, High Bank Marl, Shell Layer Marl, Under Shell Layer Marl, Sand Marl, Green Marl, Grey Marl and Clayey Marl

Features

Blocks negativity, Helps to protect against depression

Generally rough to touch, Is one of the oldest rock, Splintery, Very fine grained rock

Archaeological Significance

Monuments

Famous Monuments

Sculpture

Famous Sculptures

Pictographs

Petroglyphs

Figurines

Fossils

Absent

Present

Formation

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.

Marl forms when very fine-grained clay particles are deposited in water which settles at the bottom of water bodies and are compacted by overlying sediment; the water squeezes out and hence forming Marl rock.

Composition

Mineral Content

Calcite, Clay, Dolomite, Gypsum, Micas, Pyrite, Quartz

Compound Content

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

Aluminium Oxide, NaCl, CaO, Iron(III) Oxide, Silicon Dioxide

Transformation

Metamorphism

✔ ✘

Types of Metamorphism

Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Biological Weathering, Chemical Weathering

Erosion

✔ ✘

Types of Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Chemical Erosion, Coastal Erosion, Water Erosion, Wind Erosion

Properties

Physical Properties

Hardness

5-5.52-3

1 7

👆🏻

Grain Size

Very fine-grained

Fracture

Conchoidal

Streak

White

Porosity

Very Less Porous

Highly Porous

Luster

Vitreous

Dull

Compressive Strength

0.15 N/mm²30.00 N/mm²

0.15 450

👆🏻

Cleavage

Toughness

2.6

Specific Gravity

2.6-2.72.2-2.8

0 8.4

👆🏻

Transparency

Translucent

Opaque

Density

2.6 g/cm³2.4-2.8 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.92 kJ/Kg K0.80 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant

Reserves

Deposits in Eastern Continents

Asia

Afghanistan, Indonesia, Japan, Russia

India, Pakistan, Russia

Africa

Kenya

Ethiopia, Kenya, Morocco, South Africa

Europe

Greece, Hungary, Iceland, Italy, Turkey

Austria, France, Germany, Greece, Italy, Romania, Scotland, Spain, Switzerland

Others

Deposits in Western Continents

North America

Canada, Mexico, USA

USA

South America

Argentina, Chile, Ecuador, Peru

Colombia, Ecuador, Peru

Deposits in Oceania Continent

Australia

New Zealand

New South Wales, Victoria, Western Australia

All about Obsidian and Marl Properties

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