Definition
Comendite is a hard, peralkaline igneous rock, a type of light blue grey rhyolite
  
Variolites are a group of dark green basic igneous rocks which exhibit pale colored spots, or spherules, especially on weathered surfaces, that give them a pockmarked appearance
  
History
  
  
Origin
Italy
  
France
  
Discoverer
Unknown
  
Unknown
  
Etymology
Comendite derives its name from the area of Le Commende on San Pietro Island in Italy
  
From Latin varius, speckled, variegated
  
Class
Igneous Rocks
  
Igneous Rocks
  
Sub-Class
Durable Rock, Hard Rock
  
Durable Rock, Hard Rock
  
Family
  
  
Group
Volcanic
  
Volcanic
  
Other Categories
Medium Grained Rock, Opaque Rock
  
Opaque Rock
  
Texture
Porphyritic
  
Glassy, Massive, Porphyritic, Scoriaceous, Vesicular
  
Color
Blue, Bluish - Grey
  
Black, Brown, Light to Dark Grey
  
Maintenance
Less
  
Less
  
Durability
Durable
  
Durable
  
Water Resistant
Yes
  
Yes
  
Scratch Resistant
Yes
  
Yes
  
Stain Resistant
Yes
  
No
  
Wind Resistant
Yes
  
No
  
Acid Resistant
Yes
  
Yes
  
Appearance
Foliated
  
Dull and Soft
  
Architecture
  
  
Interior Uses
Countertops, Decorative Aggregates, Interior Decoration
  
Floor Tiles, Flooring, Homes, Hotels, Kitchens
  
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration
  
Garden Decoration, Office Buildings
  
Other Architectural Uses
Curbing
  
Curbing
  
Industry
  
  
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, Cobblestones, Rail Track Ballast, Roadstone
  
Medical Industry
Not Yet Used
  
Not Yet Used
  
Antiquity Uses
Artifacts
  
Artifacts, Monuments, Sculpture
  
Other Uses
  
  
Commercial Uses
Cemetery Markers
  
Cemetery Markers, Creating Artwork
  
Types
Rhyolite
  
Not Available
  
Features
Very fine grained rock, It is One of the Oldest, Strongest and Hardest Rock
  
Has High structural resistance against erosion and climate, Very fine grained rock
  
Archaeological Significance
  
  
Monuments
Not Yet Used
  
Used
  
Famous Monuments
Not Applicable
  
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
  
Fossils
Absent
  
Absent
  
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.
  
Variolites are a group of dark green basic igneous rocks that exhibit pale colored spots on weathered surfaces that give them a pockmarked appearance.
  
Composition
  
  
Mineral Content
Albite, Amphibole, Quartz
  
Olivine, Plagioclase, Pyroxene
  
Compound Content
Al, Fe, Potassium Oxide
  
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
  
Transformation
  
  
Metamorphism
Yes
  
Yes
  
Types of Metamorphism
Cataclastic Metamorphism, Regional Metamorphism
  
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
  
Weathering
Yes
  
Yes
  
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
  
Biological Weathering, Chemical Weathering, Mechanical Weathering
  
Erosion
Yes
  
No
  
Types of Erosion
Coastal Erosion, Water Erosion
  
Not Applicable
  
Physical Properties
  
  
Hardness
6-7
  
6
  
Grain Size
Medium Grained
  
Not Applicable
  
Fracture
Pervasive
  
Conchoidal
  
Streak
Bluish Black
  
White to Grey
  
Porosity
Highly Porous
  
Less Porous
  
Luster
Dull
  
Not Available
  
Compressive Strength
92.40 N/mm2
  
21
37.50 N/mm2
  
27
Cleavage
Not Available
  
Not Available
  
Toughness
2
  
2.3
  
Specific Gravity
2.38
  
2.8-3
  
Transparency
Opaque
  
Opaque
  
Density
Not Available
  
2.9-3.1 g/cm3
  
Thermal Properties
  
  
Specific Heat Capacity
Not Available
  
0.84 kJ/Kg K
  
15
Resistance
Heat Resistant, Impact Resistant
  
Heat Resistant, Pressure Resistant, Wear Resistant
  
Deposits in Eastern Continents
  
  
Asia
China
  
India, Russia
  
Africa
East Africa
  
South Africa
  
Europe
Italy
  
Iceland
  
Others
Not Yet Found
  
Not Yet Found
  
Deposits in Western Continents
  
  
North America
Not Yet Found
  
Canada, USA
  
South America
Not Yet Found
  
Brazil
  
Deposits in Oceania Continent
  
  
Australia
Queensland
  
Not Yet Found
  
Comendite vs Variolite 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 Variolite characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Comendite and Properties of Variolite. Learn more about Comendite vs Variolite in the next section. The interior uses of Comendite include Countertops, Decorative aggregates and Interior decoration whereas the interior uses of Variolite include Floor tiles, Flooring, Homes, Hotels and Kitchens. Due to some exceptional properties of Comendite and Variolite, 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 Variolite include As dimension stone, Cobblestones, Rail track ballast, Roadstone.
More about Comendite and Variolite
Here you can know more about Comendite and Variolite. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Comendite and Variolite consists of mineral content and compound content. The mineral content of Comendite includes Albite, Amphibole, Quartz and mineral content of Variolite includes Olivine, Plagioclase, Pyroxene. You can also check out the list of all Igneous Rocks. When we have to compare Comendite vs Variolite, the texture, color and appearance plays an important role in determining the type of rock. Comendite is available in blue, bluish - grey colors whereas, Variolite is available in black, brown, light to dark grey colors. Appearance of Comendite is Foliated and that of Variolite is Dull and Soft. Properties of rock is another aspect for Comendite vs Variolite. The hardness of Comendite is 6-7 and that of Variolite is 6. The types of Comendite are Rhyolite whereas types of Variolite are Not Available. 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 Variolite is white to grey. The specific heat capacity of Comendite is Not Available and that of Variolite 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.Comendite is heat resistant, impact resistant whereas Variolite is heat resistant, pressure resistant, wear resistant.