Coquina and Rhyolite
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
Rhyolite is a fine-grained igneous rock which is rich in silica
History
Origin
European Foreland Basins
North America
Discoverer
Unknown
Ferdinand von Richthofen
Etymology
From Concha (Latin)+ Coquina(Spanish) +conch(English)= Couquina (mid 19th century)
From German Rhyolit, from Greek rhuax lava stream + lithos stone
Class
Sedimentary Rocks
Igneous Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Hard Rock
Family
Group
Not Applicable
Volcanic
Other Categories
Coarse Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock
Texture
Texture
Clastic
Aphanitic, Glassy, Porphyritic
Color
Beige, Buff, Orange
Grey, White, Light Black
Maintenance
More
More
Durability
Non-Durable
Durable
Water Resistant
No
Yes
Scratch Resistant
No
Yes
Stain Resistant
No
Yes
Wind Resistant
No
Yes
Acid Resistant
No
Yes
Appearance
Layered, Banded, Veined and Shiny
Banded
Uses
Architecture
Interior Uses
Decorative Aggregates, Homes, Hotels, Interior Decoration
Decorative Aggregates, Homes, Hotels, Interior Decoration, Kitchens
Exterior Uses
Garden Decoration, Office Buildings
As Building Stone, As Facing Stone, Paving Stone, Office Buildings
Other Architectural Uses
Curbing
Not Yet Used
Industry
Construction Industry
Building houses or walls, Construction Aggregate
Arrowheads, As Dimension Stone, Building houses or walls, Construction Aggregate, Cutting Tool, for Road Aggregate, Knives
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
Artifacts
Other Uses
Commercial Uses
Creating Artwork
Gemstone, Laboratory bench tops, Jewelry
Types
Types
Not Available
Pumice Rocks, Obsidian Rocks, Perlite Rocks, Porphyritic Rocks.
Features
Available in Lots of Colors and Patterns, Is one of the oldest rock
Acidic in nature, Available in lots of colors
Archaeological Significance
Monuments
Used
Not Yet Used
Famous Monuments
Data Not Available
Not Applicable
Sculpture
Used
Not Yet Used
Famous Sculptures
Data Not Available
Not Applicable
Pictographs
Used
Not Used
Petroglyphs
Used
Not 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.
Rhyolite is a felsic extrusive rock and due to its high silica content, rhyolite lava is very viscous and is volcanic equivalent of granite.
Composition
Mineral Content
Apatite, Augite, Bronzite, Calcite, Chert, Chlorite, Clay Minerals, Epidote, Feldspar, Garnet, Micas, Muscovite or Illite
Biotite, Feldspar, Hornblade, Plagioclase, Pyroxene, Quartz
Compound Content
CaO, Carbon Dioxide, Iron(III) Oxide, MgO
Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide, Sodium
Transformation
Metamorphism
No
Yes
Types of Metamorphism
Not Applicable
Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism
Weathering
Yes
Yes
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Erosion
Yes
Yes
Types of Erosion
Coastal Erosion, Sea Erosion, Water Erosion, Wind Erosion
Chemical Erosion, Sea Erosion, Water Erosion, Wind Erosion
Properties
Physical Properties
Hardness
1-2
6-7
Grain Size
Coarse Grained
Large and Coarse Grained
Fracture
Irregular
Sub-conchoidal
Streak
White
Colorless
Porosity
Highly Porous
Highly Porous
Luster
Dull to Vitreous to Submetallic
Earthy
Compressive Strength
Not Available
140.00 N/mm2
15
Cleavage
Not Available
Not Available
Toughness
Not Available
2
Specific Gravity
1.10-2.24
2.65-2.67
Transparency
Opaque
Opaque
Density
2.8-2.9 g/cm3
2.4-2.6 g/cm3
Thermal Properties
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Wear Resistant
Reserves
Deposits in Eastern Continents
Asia
Not Yet Found
China, India
Africa
Not Yet Found
Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa
Europe
United Kingdom
Germany, Iceland, Ireland, Italy, Spain
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
USA
Canada, USA
South America
Not Yet Found
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Deposits in Oceania Continent
Australia
Not Yet Found
New Zealand, Queensland, Western Australia
All about Coquina and Rhyolite Properties
Know all about Coquina and Rhyolite properties here. All properties of rocks are important as they define the type of rock and its application. Coquina belongs to Sedimentary Rocks while Rhyolite belongs to Igneous Rocks.Texture of Coquina is Clastic whereas that of Rhyolite is Aphanitic, Glassy, Porphyritic. Coquina appears Layered, Banded, Veined and Shiny and Rhyolite appears Banded. The luster of Coquina is dull to vitreous to submetallic while that of Rhyolite is earthy. Coquina is available in beige, buff, orange colors whereas Rhyolite is available in grey, white, light black colors. The commercial uses of Coquina are creating artwork and that of Rhyolite are gemstone, laboratory bench tops, jewelry.
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