Definition
Comendite is a hard, peralkaline igneous rock, a type of light blue grey rhyolite
Dacite is a volcanic igneous rock which is rintermediate in composition between andesite and rhyolite
Origin
Italy
Romania and Moldova, Europe
Discoverer
Unknown
Unknown
Etymology
Comendite derives its name from the area of Le Commende on San Pietro Island in Italy
From Dacia, a province of the Roman Empire which lay between the Danube River and Carpathian Mountains where the rock was first described
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Soft Rock
Other Categories
Medium Grained Rock, Opaque Rock
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Porphyritic
Aphanitic to Porphyritic
Color
Blue, Bluish - Grey
Bluish - Grey, Brown, Grey, Light to Dark Grey
Durability
Durable
Durable
Appearance
Foliated
Vesicular
Interior Uses
Countertops, Decorative Aggregates, Interior Decoration
Decorative Aggregates, Entryways, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration
As Building Stone, Paving Stone, Garden Decoration
Other Architectural Uses
Curbing
Curbing
Construction Industry
Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate, Landscaping, Making natural cement, Raw material for the manufacture of mortar
As Dimension Stone, Construction Aggregate, for Road Aggregate, Landscaping
Antiquity Uses
Artifacts
Artifacts
Commercial Uses
Cemetery Markers
Commemorative Tablets, Creating Artwork
Types
Rhyolite
Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite
Features
Very fine grained rock, It is One of the Oldest, Strongest and Hardest Rock
Host Rock for Lead, Is one of the oldest rock
Archaeological Significance
Formation
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.
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.
Mineral Content
Albite, Amphibole, Quartz
Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon
Compound Content
Al, Fe, Potassium Oxide
Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide
Types of Metamorphism
Cataclastic Metamorphism, Regional Metamorphism
Burial Metamorphism, Cataclastic Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Coastal Erosion, Water Erosion
Chemical Erosion
Grain Size
Medium Grained
Medium to Fine Coarse Grained
Fracture
Pervasive
Conchoidal
Streak
Bluish Black
White
Porosity
Highly Porous
Less Porous
Luster
Dull
Subvitreous to Dull
Specific Gravity
2.38
2.86-2.87
Transparency
Opaque
Translucent
Density
-9999 g/cm3
2.77-2.771 g/cm3
Resistance
Heat Resistant, Impact Resistant
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Europe
Italy
France, Greece, Romania, Scotland, Spain
Deposits in Western Continents
South America
-
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Deposits in Oceania Continent
Australia
Queensland
New Zealand, South Australia, Western Australia
Comendite vs Dacite 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. Comendite vs Dacite characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Comendite and Properties of Dacite. Learn more about Comendite vs Dacite in the next section. The interior uses of Comendite include Countertops, Decorative aggregates and Interior decoration whereas the interior uses of Dacite include Decorative aggregates, Entryways and Interior decoration. Due to some exceptional properties of Comendite and Dacite, they have various applications in construction industry. The uses of Comendite in construction industry include Building houses or walls, Cement manufacture, Construction aggregate, For road aggregate, Landscaping, Making natural cement, Raw material for the manufacture of mortar and that of Dacite include As dimension stone, Construction aggregate, For road aggregate, Landscaping.
More about Comendite and Dacite
Here you can know more about Comendite and Dacite. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Comendite and Dacite consists of mineral content and compound content. The mineral content of Comendite includes Albite, Amphibole, Quartz and mineral content of Dacite includes Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon. You can also check out the list of all Igneous Rocks. When we have to compare Comendite vs Dacite, the texture, color and appearance plays an important role in determining the type of rock. Comendite is available in blue, bluish - grey colors whereas, Dacite is available in bluish - grey, brown, grey, light to dark grey colors. Appearance of Comendite is Foliated and that of Dacite is Vesicular. Properties of rock is another aspect for Comendite vs Dacite. The hardness of Comendite is 6-7 and that of Dacite is 2-2.25. The types of Comendite are Rhyolite whereas types of Dacite are Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Comendite is bluish black while that of Dacite is white. The specific heat capacity of Comendite is 0.79 kJ/Kg K and that of Dacite is 0.92 kJ/Kg K. Depending on the properties like hardness, toughness, specific heat capacity, porosity etc., rocks are resistant to heat, wear, impact, etc.Comendite is heat resistant, impact resistant whereas Dacite is heat resistant, impact resistant, pressure resistant, wear resistant.