Coquina and Hornfels
Definition
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
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
History
Origin
European Foreland Basins
New Zealand
Discoverer
Unknown
Unknown
Etymology
From Concha (Latin)+ Coquina(Spanish) +conch(English)= Couquina (mid 19th century)
From German which means hornstone
Class
Sedimentary Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Soft Rock
Family
Group
Not Applicable
Not Applicable
Other Categories
Coarse Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Texture
Clastic
Granular, Platy
Color
Beige, Buff, Orange
Brown, Dark Greenish - Grey, Green, Reddish Brown
Maintenance
More
Less
Durability
Non-Durable
Durable
Water Resistant
No
Yes
Scratch Resistant
No
No
Stain Resistant
No
No
Wind Resistant
No
No
Acid Resistant
No
No
Appearance
Layered, Banded, Veined and Shiny
Dull
Uses
Architecture
Interior Uses
Decorative Aggregates, Homes, Hotels, Interior Decoration
Decorative Aggregates, Flooring, Homes, Interior Decoration
Exterior Uses
Garden Decoration, Office Buildings
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
Other Architectural Uses
Curbing
Curbing
Industry
Construction Industry
Building houses or walls, Construction Aggregate
for Road Aggregate, Roadstone
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
Artifacts, Monuments
Other Uses
Commercial Uses
Creating Artwork
Cemetery Markers, Commemorative Tablets, Creating Artwork
Types
Types
Not Available
Biotite hornfels
Features
Available in Lots of Colors and Patterns, Is one of the oldest rock
Smooth to touch
Archaeological Significance
Monuments
Used
Used
Famous Monuments
Data Not Available
Data Not Available
Sculpture
Used
Not Yet Used
Famous Sculptures
Data Not Available
Not Applicable
Pictographs
Used
Used
Petroglyphs
Used
Used
Figurines
Used
Not Yet Used
Fossils
Present
Absent
Formation
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.
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.
Composition
Mineral Content
Apatite, Augite, Bronzite, Calcite, Chert, Chlorite, Clay Minerals, Epidote, Feldspar, Garnet, Micas, Muscovite or Illite
Andalusite
Compound Content
CaO, Carbon Dioxide, Iron(III) Oxide, MgO
Fe, Mg
Transformation
Metamorphism
No
No
Types of Metamorphism
Not Applicable
Not Applicable
Weathering
Yes
Yes
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering
Erosion
Yes
Yes
Types of Erosion
Coastal Erosion, Sea Erosion, Water Erosion, Wind Erosion
Chemical Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Properties
Physical Properties
Hardness
1-2
2-3
Grain Size
Coarse Grained
Fine Grained
Fracture
Irregular
Conchoidal
Streak
White
Unknown
Porosity
Highly Porous
Highly Porous
Luster
Dull to Vitreous to Submetallic
Shiny
Compressive Strength
Not Available
5.80 N/mm2
31
Cleavage
Not Available
Perfect
Toughness
Not Available
Not Yet Found
Specific Gravity
1.10-2.24
3.4-3.9
Transparency
Opaque
Opaque
Density
2.8-2.9 g/cm3
0.25-0.30 g/cm3
Thermal Properties
Specific Heat Capacity
Not Available
0.84 kJ/Kg K
15
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Impact Resistant, Pressure Resistant
Reserves
Deposits in Eastern Continents
Asia
Not Yet Found
Bangladesh, Bhutan, China, India, North Korea, Qatar, Russia, Saudi Arabia, South Korea, Thailand
Africa
Not Yet Found
Cameroon, East Africa, Tanzania, Western Africa
Europe
United Kingdom
United Kingdom
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
USA
Canada, USA
South America
Not Yet Found
Bolivia, Brazil, Colombia, Ecuador
Deposits in Oceania Continent
Australia
Not Yet Found
New South Wales, New Zealand, Queensland, Western Australia
All about Coquina and Hornfels Properties
Know all about Coquina and Hornfels properties here. All properties of rocks are important as they define the type of rock and its application. Coquina belongs to Sedimentary Rocks while Hornfels belongs to Metamorphic Rocks.Texture of Coquina is Clastic whereas that of Hornfels is Granular, Platy. Coquina appears Layered, Banded, Veined and Shiny and Hornfels appears Dull. The luster of Coquina is dull to vitreous to submetallic while that of Hornfels is shiny. Coquina is available in beige, buff, orange colors whereas Hornfels is available in brown, dark greenish - grey, green, reddish brown colors. The commercial uses of Coquina are creating artwork and that of Hornfels are cemetery markers, commemorative tablets, creating artwork.
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