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Hornfels
Hornfels

Coquina
Coquina



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Definition

Definition

Hornfels is a metamorphic rock formed by the contact between mudstone or other clay rich rock, and a hot igneous body, and represents a heat altered equivalent of the original rock
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

History

Origin

New Zealand
European Foreland Basins

Discoverer

Unknown
Unknown

Etymology

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

Class

Metamorphic Rocks
Sedimentary Rocks

Sub-Class

Durable Rock, Soft Rock
Durable Rock, Soft Rock

Family

Group

-
-

Other Categories

Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock

Texture

Texture

Granular, Platy
Clastic

Color

Brown, Dark Greenish - Grey, Green, Reddish Brown
Beige, Buff, Orange

Maintenance

Less
More

Durability

Durable
Non-Durable

Water Resistant

Scratch Resistant

Stain Resistant

Wind Resistant

Acid Resistant

Appearance

Dull
Layered, Banded, Veined and Shiny

Uses

Architecture

Interior Uses

Decorative Aggregates, Flooring, Homes, Interior Decoration
Decorative Aggregates, Homes, Hotels, Interior Decoration

Exterior Uses

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

Other Architectural Uses

Curbing
Curbing

Industry

Construction Industry

for Road Aggregate, Roadstone
Building houses or walls, Construction Aggregate

Medical Industry

-
-

Antiquity Uses

Artifacts, Monuments
Artifacts, Monuments, Sculpture, Small Figurines

Other Uses

Commercial Uses

Cemetery Markers, Commemorative Tablets, Creating Artwork
Creating Artwork

Types

Types

Biotite hornfels
Sedimentary rock

Features

Smooth to touch
Available in Lots of Colors and Patterns, Is one of the oldest rock

Archaeological Significance

Monuments

-
-

Famous Monuments

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-

Sculpture

-
-

Famous Sculptures

-
-

Pictographs

-
-

Petroglyphs

-
-

Figurines

-
-

Fossils

Absent
Present

Formation

Formation

Due to change in environmental conditions, rocks are heated and pressurized deep inside the Earth's surface. Hornfels is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.
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.

Composition

Mineral Content

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

Compound Content

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

Transformation

Metamorphism

Types of Metamorphism

-
-

Weathering

Types of Weathering

Biological Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering

Erosion

Types of Erosion

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

Properties

Physical Properties

Hardness

2-31-2
1 7
👆🏻

Grain Size

Fine Grained
Coarse Grained

Fracture

Conchoidal
Irregular

Streak

-
White

Porosity

Highly Porous
Highly Porous

Luster

Shiny
Dull to Vitreous to Submetallic

Compressive Strength

5.80 N/mm2-
0.15 450
👆🏻

Cleavage

Perfect
-

Toughness

-
-

Specific Gravity

3.4-3.91.10-2.24
0 8.4
👆🏻

Transparency

Opaque
Opaque

Density

0.25-0.30 g/cm32.8-2.9 g/cm3
0 1400
👆🏻

Thermal Properties

Specific Heat Capacity

0.84 kJ/Kg K0.84 kJ/Kg K
0.14 3.2
👆🏻

Resistance

Heat Resistant, Impact Resistant, Pressure Resistant
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant

Reserves

Deposits in Eastern Continents

Asia

Bangladesh, Bhutan, China, India, North Korea, Qatar, Russia, Saudi Arabia, South Korea, Thailand
-

Africa

Cameroon, East Africa, Tanzania, Western Africa
-

Europe

United Kingdom
United Kingdom

Others

-
-

Deposits in Western Continents

North America

Canada, USA
USA

South America

Bolivia, Brazil, Colombia, Ecuador
-

Deposits in Oceania Continent

Australia

New South Wales, New Zealand, Queensland, Western Australia
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