Coquina

Obsidian

Coquina and Obsidian

Coquina

Obsidian

Add ⊕

Definition

Coquina is a sedimentary rock that is composed either wholly or almost entirely of the transported, abraded, and mechanically-sorted fragments of the shells of molluscs, trilobites, brachiopods, or other invertebrates

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

European Foreland Basins

Ethiopia

Discoverer

Unknown

Obsius

Etymology

From Concha (Latin)+ Coquina(Spanish) +conch(English)= Couquina (mid 19th century)

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

Class

Sedimentary Rocks

Igneous Rocks

Sub-Class

Durable Rock, Soft Rock

Durable Rock, Medium Hardness Rock

Family

Group

Volcanic

Other Categories

Coarse Grained Rock, Opaque Rock

Opaque Rock

Texture

Clastic

Glassy

Color

Beige, Buff, Orange

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

Maintenance

Less

Durability

Non-Durable

Durable

Water Resistant

✔ ✘

Scratch Resistant

✔ ✘

Stain Resistant

✔ ✘

Wind Resistant

✔ ✘

Acid Resistant

✔ ✘

Appearance

Layered, Banded, Veined and Shiny

Shiny

Uses

Architecture

Interior Uses

Decorative Aggregates, Homes, Hotels, Interior Decoration

Decorative Aggregates, Interior Decoration

Exterior Uses

Garden Decoration, Office Buildings

Garden Decoration

Other Architectural Uses

Curbing

Industry

Construction Industry

Building houses or walls, Construction Aggregate

Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points

Medical Industry

Surgery

Antiquity Uses

Artifacts, Monuments, Sculpture, Small Figurines

Artifacts, Jewellery

Other Uses

Commercial Uses

Creating Artwork

Creating Artwork, Mirror, Used in aquariums

Types

Sedimentary rock

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

Features

Available in Lots of Colors and Patterns, 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

Present

Absent

Formation

Coquina is a sedimentary rock which is formed when billions of small clam-like seashell, called Coquina, or cockleshell are die and hence are deposited, buried and turns into a rock when pressure is applied.

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

Apatite, Augite, Bronzite, Calcite, Chert, Chlorite, Clay Minerals, Epidote, Feldspar, Garnet, Micas, Muscovite or Illite

Compound Content

CaO, Carbon Dioxide, Iron(III) Oxide, MgO

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, Cataclastic Metamorphism, Contact Metamorphism

Weathering

✔ ✘

Types of Weathering

Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

✔ ✘

Types of Erosion

Coastal Erosion, Sea Erosion, Water Erosion, Wind Erosion

Chemical Erosion, Coastal Erosion, Glacier Erosion

Properties

Physical Properties

Hardness

1-25-5.5

1 7

👆🏻

Grain Size

Coarse Grained

Fracture

Irregular

Conchoidal

Streak

White

Porosity

Highly Porous

Very Less Porous

Luster

Dull to Vitreous to Submetallic

Vitreous

Compressive Strength

-0.15 N/mm²

0.15 450

👆🏻

Cleavage

Toughness

Specific Gravity

1.10-2.242.6-2.7

0 8.4

👆🏻

Transparency

Opaque

Translucent

Density

2.8-2.9 g/cm³2.6 g/cm³

0 1400

👆🏻

Thermal Properties

Specific Heat Capacity

0.84 kJ/Kg K0.92 kJ/Kg K

0.14 3.2

👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Heat Resistant, Impact Resistant

Reserves

Deposits in Eastern Continents

Asia

Afghanistan, Indonesia, Japan, Russia

Africa

Kenya

Europe

United Kingdom

Greece, Hungary, Iceland, Italy, Turkey

Others

Deposits in Western Continents

North America

USA

Canada, Mexico, USA

South America

Argentina, Chile, Ecuador, Peru

Deposits in Oceania Continent

Australia

New Zealand

All about Coquina and Obsidian Properties

Know all about Coquina and Obsidian properties here. All properties of rocks are important as they define the type of rock and its application. Coquina belongs to Sedimentary Rocks while Obsidian belongs to Igneous Rocks.Texture of Coquina is Clastic whereas that of Obsidian is Glassy. Coquina appears Layered, Banded, Veined and Shiny and Obsidian appears Shiny. The luster of Coquina is dull to vitreous to submetallic while that of Obsidian is vitreous. Coquina is available in beige, buff, orange colors whereas Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors. The commercial uses of Coquina are creating artwork and that of Obsidian are creating artwork, mirror, used in aquariums.