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
Comendite is a hard, peralkaline igneous rock, a type of light blue grey rhyolite
Origin
European Foreland Basins
Italy
Discoverer
Unknown
Unknown
Etymology
From Concha (Latin)+ Coquina(Spanish) +conch(English)= Couquina (mid 19th century)
Comendite derives its name from the area of Le Commende on San Pietro Island in Italy
Class
Sedimentary Rocks
Igneous Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Hard Rock
Other Categories
Coarse Grained Rock, Opaque Rock
Medium Grained Rock, Opaque Rock
Texture
Clastic
Porphyritic
Color
Beige, Buff, Orange
Blue, Bluish - Grey
Durability
Non-Durable
Durable
Appearance
Layered, Banded, Veined and Shiny
Foliated
Interior Uses
Decorative Aggregates, Homes, Hotels, Interior Decoration
Countertops, Decorative Aggregates, Interior Decoration
Exterior Uses
Garden Decoration, Office Buildings
As Building Stone, As Facing Stone, Garden Decoration
Other Architectural Uses
Curbing
Curbing
Construction Industry
Building houses or walls, Construction Aggregate
Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate, Landscaping, Making natural cement, Raw material for the manufacture of mortar
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
Artifacts
Commercial Uses
Creating Artwork
Cemetery Markers
Types
Sedimentary rock
Rhyolite
Features
Available in Lots of Colors and Patterns, Is one of the oldest rock
Very fine grained rock, It is One of the Oldest, Strongest and Hardest Rock
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.
Comendite is a type of Igneous rock which is formed due to cooling and solidification of lava or magma. It may form 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
Albite, Amphibole, Quartz
Compound Content
CaO, Carbon Dioxide, Iron(III) Oxide, MgO
Al, Fe, Potassium Oxide
Types of Metamorphism
-
Cataclastic 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
Coastal Erosion, Water Erosion
Grain Size
Coarse Grained
Medium Grained
Fracture
Irregular
Pervasive
Streak
White
Bluish Black
Porosity
Highly Porous
Highly Porous
Luster
Dull to Vitreous to Submetallic
Dull
Specific Gravity
1.10-2.24
2.38
Transparency
Opaque
Opaque
Density
2.8-2.9 g/cm3
-9999 g/cm3
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Impact Resistant
Deposits in Eastern Continents
Europe
United Kingdom
Italy
Deposits in Western Continents
Deposits in Oceania Continent