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
Tephrite is an aphanitic to porphyritic textured, volcanic igneous rock
Origin
European Foreland Basins
Germany
Discoverer
Unknown
Van Tooren
Etymology
From Concha (Latin)+ Coquina(Spanish) +conch(English)= Couquina (mid 19th century)
From Greek tephra, ashes from Indo-European base, to burn
Class
Sedimentary Rocks
Igneous Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Hard Rock
Other Categories
Coarse Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Clastic
Aphanitic to Porphyritic
Color
Beige, Buff, Orange
Black, Brown, Green, Grey, White
Durability
Non-Durable
Durable
Appearance
Layered, Banded, Veined and Shiny
Vesicular
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
Other Architectural Uses
Curbing
Curbing
Construction Industry
Building houses or walls, Construction Aggregate
Landscaping
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
Artifacts, Sculpture
Commercial Uses
Creating Artwork
Production of Lime, Soil Conditioner
Types
Sedimentary rock
Igneous rock
Features
Available in Lots of Colors and Patterns, Is one of the oldest rock
Host Rock for Lead
Archaeological Significance
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.
Tephrite is a fine-grained, hard rock which is a type of metasomatite, essentially altered basalt. It forms with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.
Mineral Content
Apatite, Augite, Bronzite, Calcite, Chert, Chlorite, Clay Minerals, Epidote, Feldspar, Garnet, Micas, Muscovite or Illite
Alkali feldspar, Nepheline, Plagioclase, Pyroxene
Compound Content
CaO, Carbon Dioxide, Iron(III) Oxide, MgO
CaO, Carbon Dioxide, MgO, Silicon Dioxide
Types of Metamorphism
-
Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Coastal Erosion, Sea Erosion, Water Erosion, Wind Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion
Grain Size
Coarse Grained
Medium to Fine Coarse Grained
Fracture
Irregular
Uneven
Streak
White
Bluish Black
Porosity
Highly Porous
Very Less Porous
Luster
Dull to Vitreous to Submetallic
Subvitreous to Dull
Cleavage
-
Crenulation and Pervasive
Specific Gravity
1.10-2.24
2.86
Transparency
Opaque
Opaque
Density
2.8-2.9 g/cm3
2.8-2.9 g/cm3
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Impact Resistant
Deposits in Eastern Continents
Europe
United Kingdom
Germany, Hungary, Italy, Portugal, Spain
Deposits in Western Continents
Deposits in Oceania Continent
Australia
-
New Zealand, Western Australia