Essexite and Coquina
Definition
Definition
Essexite which is also known as nepheline monzogabbro, is a dark gray or black holocrystalline plutonic Iigneous 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
USA
European Foreland Basins
Discoverer
Unknown
Unknown
Etymology
From the locality in Essex County, Massachusetts,US
From Concha (Latin)+ Coquina(Spanish) +conch(English)= Couquina (mid 19th century)
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Soft Rock
Family
Group
Plutonic
Not Applicable
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock
Texture
Texture
Granular
Clastic
Color
Dark Grey to Black
Beige, Buff, Orange
Maintenance
Less
More
Durability
Durable
Non-Durable
Water Resistant
Yes
No
Scratch Resistant
Yes
No
Stain Resistant
Yes
No
Wind Resistant
Yes
No
Acid Resistant
No
No
Appearance
Banded
Layered, Banded, Veined and Shiny
Uses
Architecture
Interior Uses
Decorative Aggregates, 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
As Dimension Stone, Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate
Building houses or walls, Construction Aggregate
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
Artifacts, Monuments, Sculpture, Small Figurines
Other Uses
Commercial Uses
Cemetery Markers, Commemorative Tablets, Jewelry, Sea Defence, Tombstones
Creating Artwork
Types
Types
Not Available
Not Available
Features
Is one of the oldest rock, Smooth to touch
Available in Lots of Colors and Patterns, Is one of the oldest rock
Archaeological Significance
Monuments
Used
Used
Famous Monuments
Data Not Available
Data Not Available
Sculpture
Used
Used
Famous Sculptures
Data Not Available
Data Not Available
Pictographs
Not Used
Used
Petroglyphs
Not Used
Used
Figurines
Used
Used
Fossils
Absent
Present
Formation
Formation
Essexite is a type of igneous rock, which is usually dark grey to black plutonic rock. For the formation of essexite, suitable magma with exact composition of K, Ba, Rb, Cs, Sr should be produced.
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
Augite, Feldspar, Hornblende, Nepheline, Olivine, Plagioclase, Pyroxene
Apatite, Augite, Bronzite, Calcite, Chert, Chlorite, Clay Minerals, Epidote, Feldspar, Garnet, Micas, Muscovite or Illite
Compound Content
Aluminium Oxide, Ba, Ca, Cs, Potassium, Rb, Sodium, Sr
CaO, Carbon Dioxide, Iron(III) Oxide, MgO
Transformation
Metamorphism
Yes
No
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism
Not Applicable
Weathering
Yes
Yes
Types of Weathering
Biological Weathering, Chemical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Erosion
Yes
Yes
Types of Erosion
Coastal Erosion, Glacier Erosion, Water Erosion
Coastal Erosion, Sea Erosion, Water Erosion, Wind Erosion
Properties
Physical Properties
Hardness
7
1-2
Grain Size
Fine Grained
Coarse Grained
Fracture
Conchoidal
Irregular
Streak
Black
White
Porosity
Highly Porous
Highly Porous
Luster
Not Available
Dull to Vitreous to Submetallic
Cleavage
Not Available
Not Available
Toughness
1.6
Not Available
Specific Gravity
Not Available
1.10-2.24
Transparency
Opaque
Opaque
Density
Not Available
2.8-2.9 g/cm3
Thermal Properties
Resistance
Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Reserves
Deposits in Eastern Continents
Asia
India, Russia
Not Yet Found
Africa
South Africa
Not Yet Found
Europe
Germany, Greece, Italy, Scotland, Turkey
United Kingdom
Others
Greenland
Not Yet Found
Deposits in Western Continents
North America
Canada, USA
USA
South America
Brazil, Colombia, Venezuela
Not Yet Found
Deposits in Oceania Continent
Australia
New Zealand, Queensland
Not Yet Found
All about Essexite and Coquina Properties
Know all about Essexite and Coquina properties here. All properties of rocks are important as they define the type of rock and its application. Essexite belongs to Igneous Rocks while Coquina belongs to Sedimentary Rocks.Texture of Essexite is Granular whereas that of Coquina is Clastic. Essexite appears Banded and Coquina appears Layered, Banded, Veined and Shiny. The luster of Essexite is not available while that of Coquina is dull to vitreous to submetallic. Essexite is available in dark grey to black colors whereas Coquina is available in beige, buff, orange colors. The commercial uses of Essexite are cemetery markers, commemorative tablets, jewelry, sea defence, tombstones and that of Coquina are creating artwork.
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