Definition
Dacite is a volcanic igneous rock which is rintermediate in composition between andesite and rhyolite
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
Romania and Moldova, Europe
European Foreland Basins
Discoverer
Unknown
Unknown
Etymology
From Dacia, a province of the Roman Empire which lay between the Danube River and Carpathian Mountains where the rock was first described
From Concha (Latin)+ Coquina(Spanish) +conch(English)= Couquina (mid 19th century)
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Soft Rock
Other Categories
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock
Texture
Aphanitic to Porphyritic
Clastic
Color
Bluish - Grey, Brown, Grey, Light to Dark Grey
Beige, Buff, Orange
Durability
Durable
Non-Durable
Appearance
Vesicular
Layered, Banded, Veined and Shiny
Interior Uses
Decorative Aggregates, Entryways, Interior Decoration
Decorative Aggregates, Homes, Hotels, Interior Decoration
Exterior Uses
As Building Stone, Paving Stone, Garden Decoration
Garden Decoration, Office Buildings
Other Architectural Uses
Curbing
Curbing
Construction Industry
As Dimension Stone, Construction Aggregate, for Road Aggregate, Landscaping
Building houses or walls, Construction Aggregate
Antiquity Uses
Artifacts
Artifacts, Monuments, Sculpture, Small Figurines
Commercial Uses
Commemorative Tablets, Creating Artwork
Creating Artwork
Types
Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite
Sedimentary rock
Features
Host Rock for Lead, Is one of the oldest rock
Available in Lots of Colors and Patterns, Is one of the oldest rock
Archaeological Significance
Formation
Dacitic magma is formed by the subduction of young oceanic crust under a thick felsic continental plate. Further, the Oceanic crust is hydrothermally altered as quartz and sodium are added.
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
Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon
Apatite, Augite, Bronzite, Calcite, Chert, Chlorite, Clay Minerals, Epidote, Feldspar, Garnet, Micas, Muscovite or Illite
Compound Content
Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide
CaO, Carbon Dioxide, Iron(III) Oxide, MgO
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism
-
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion
Coastal Erosion, Sea Erosion, Water Erosion, Wind Erosion
Grain Size
Medium to Fine Coarse Grained
Coarse Grained
Fracture
Conchoidal
Irregular
Porosity
Less Porous
Highly Porous
Luster
Subvitreous to Dull
Dull to Vitreous to Submetallic
Specific Gravity
2.86-2.87
1.10-2.24
Transparency
Translucent
Opaque
Density
2.77-2.771 g/cm3
2.8-2.9 g/cm3
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Europe
France, Greece, Romania, Scotland, Spain
United Kingdom
Deposits in Western Continents
South America
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
-
Deposits in Oceania Continent
Australia
New Zealand, South Australia, Western Australia
-
Dacite vs Coquina Characteristics
Though some rocks look identical, they have certain characteristics which distinguish them from others. Characteristics of rocks include texture, appearance, color, fracture, streak, hardness etc. Dacite vs Coquina characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Dacite and Properties of Coquina. Learn more about Dacite vs Coquina in the next section. The interior uses of Dacite include Decorative aggregates, Entryways and Interior decoration whereas the interior uses of Coquina include Decorative aggregates, Homes, Hotels and Interior decoration. Due to some exceptional properties of Dacite and Coquina, they have various applications in construction industry. The uses of Dacite in construction industry include As dimension stone, Construction aggregate, For road aggregate, Landscaping and that of Coquina include Building houses or walls, Construction aggregate.
More about Dacite and Coquina
Here you can know more about Dacite and Coquina. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Dacite and Coquina consists of mineral content and compound content. The mineral content of Dacite includes Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon and mineral content of Coquina includes Apatite, Augite, Bronzite, Calcite, Chert, Chlorite, Clay Minerals, Epidote, Feldspar, Garnet, Micas, Muscovite or Illite. You can also check out the list of all Igneous Rocks. When we have to compare Dacite vs Coquina, the texture, color and appearance plays an important role in determining the type of rock. Dacite is available in bluish - grey, brown, grey, light to dark grey colors whereas, Coquina is available in beige, buff, orange colors. Appearance of Dacite is Vesicular and that of Coquina is Layered, Banded, Veined and Shiny. Properties of rock is another aspect for Dacite vs Coquina. The hardness of Dacite is 2-2.25 and that of Coquina is 1-2. The types of Dacite are Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite whereas types of Coquina are Sedimentary rock. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Dacite and Coquina is white. The specific heat capacity of Dacite is 0.92 kJ/Kg K and that of Coquina is 0.84 kJ/Kg K. Depending on the properties like hardness, toughness, specific heat capacity, porosity etc., rocks are resistant to heat, wear, impact, etc.Dacite is heat resistant, impact resistant, pressure resistant, wear resistant whereas Coquina is heat resistant, impact resistant, pressure resistant, wear resistant.