Definition
Very fine grained fault rock which is composed of glassy matrix that often contains inclusions of wall-rock fragments.
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
Origin
USA
European Foreland Basins
Discoverer
Unknown
Unknown
Etymology
From pseudo- + tachylite, a glassy rock generated by frictional heat within faults.
From Concha (Latin)+ Coquina(Spanish) +conch(English)= Couquina (mid 19th century)
Class
Metamorphic Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Soft Rock
Group
Not Applicable
Not Applicable
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock
Color
Black, Brown, Colourless, Green, Grey, Pink, White
Beige, Buff, Orange
Durability
Durable
Non-Durable
Appearance
Dull and Soft
Layered, Banded, Veined and Shiny
Interior Uses
Decorative Aggregates, Entryways, Interior Decoration
Decorative Aggregates, Homes, Hotels, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration
Garden Decoration, Office Buildings
Other Architectural Uses
Curbing
Curbing
Construction Industry
As Dimension Stone, Cement Manufacture, for Road Aggregate, Making natural cement
Building houses or walls, Construction Aggregate
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Monuments
Artifacts, Monuments, Sculpture, Small Figurines
Commercial Uses
Creating Artwork, Gemstone
Creating Artwork
Types
Not Available
Not Available
Features
Host Rock for Lead
Available in Lots of Colors and Patterns, Is one of the oldest rock
Archaeological Significance
Famous Monuments
Data Not Available
Data Not Available
Sculpture
Not Yet Used
Used
Famous Sculptures
Not Applicable
Data Not Available
Pictographs
Not Used
Used
Petroglyphs
Not Used
Used
Figurines
Not Yet Used
Used
Formation
Due to change in environmental conditions, rocks are heated and pressurized deep inside the Earth's surface. Pseudotachylite 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.
Mineral Content
Iron Oxides, Pyroxene, Quartz, Stishovite, Sulfides
Apatite, Augite, Bronzite, Calcite, Chert, Chlorite, Clay Minerals, Epidote, Feldspar, Garnet, Micas, Muscovite or Illite
Compound Content
Carbon Dioxide, Silicon Dioxide, Sulfur Dioxide, Sulphur
CaO, Carbon Dioxide, Iron(III) Oxide, MgO
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
Not Applicable
Types of Weathering
Not Applicable
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Not Applicable
Coastal Erosion, Sea Erosion, Water Erosion, Wind Erosion
Grain Size
Very fine-grained
Coarse Grained
Fracture
Uneven
Irregular
Streak
Light to dark brown
White
Porosity
Less Porous
Highly Porous
Luster
Vitreous
Dull to Vitreous to Submetallic
Compressive Strength
Not Available
Cleavage
Irregular
Not Available
Toughness
Not Available
Not Available
Specific Gravity
2.46-2.86
1.10-2.24
Transparency
Transparent to Translucent
Opaque
Density
2.7-2.9 g/cm3
2.8-2.9 g/cm3
Specific Heat Capacity
Not Available
Resistance
Heat Resistant
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
South Korea
Not Yet Found
Africa
Western Africa
Not Yet Found
Europe
Great Britain, Switzerland
United Kingdom
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
Not Yet Found
USA
South America
Not Yet Found
Not Yet Found
Deposits in Oceania Continent
Australia
Central Australia, Western Australia
Not Yet Found
All about Pseudotachylite and Coquina Properties
Know all about Pseudotachylite and Coquina properties here. All properties of rocks are important as they define the type of rock and its application. Pseudotachylite belongs to Metamorphic Rocks while Coquina belongs to Sedimentary Rocks.Texture of Pseudotachylite is Quench whereas that of Coquina is Clastic. Pseudotachylite appears Dull and Soft and Coquina appears Layered, Banded, Veined and Shiny. The luster of Pseudotachylite is vitreous while that of Coquina is dull to vitreous to submetallic. Pseudotachylite is available in black, brown, colourless, green, grey, pink, white colors whereas Coquina is available in beige, buff, orange colors. The commercial uses of Pseudotachylite and Coquina are creating artwork, gemstone.