Definition
Gneiss is a common and widely distributed type of rock formed by high-grade regional metamorphic processes from pre-existing formations that were originally either igneous or sedimentary rocks
Comendite is a hard, peralkaline igneous rock, a type of light blue grey rhyolite
Discoverer
Unknown
Unknown
Etymology
From the Middle High German verb gneist (to spark; so called because the rock glitters)
Comendite derives its name from the area of Le Commende on San Pietro Island in Italy
Class
Metamorphic Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
Group
Not Applicable
Volcanic
Other Categories
Coarse Grained Rock, Medium Grained Rock, Opaque Rock
Medium Grained Rock, Opaque Rock
Texture
Banded, Foliated, Platy
Porphyritic
Color
Black, Brown, Pink, Red, White
Blue, Bluish - Grey
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Foliated
Foliated
Interior Uses
Countertops, Decorative Aggregates, Flooring, Interior Decoration
Countertops, Decorative Aggregates, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
As Building Stone, As Facing Stone, Garden Decoration
Other Architectural Uses
Curbing
Curbing
Construction Industry
As Dimension Stone
Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate, Landscaping, Making natural cement, Raw material for the manufacture of mortar
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts
Artifacts
Commercial Uses
Cemetery Markers, Jewelry, Tombstones, Used in aquariums
Cemetery Markers
Types
Augen Gneiss, Henderson Gneiss, Lewisian Gneiss, Archean and Proterozoic Gneiss.
Rhyolite
Features
Generally rough to touch, Is one of the oldest rock
Very fine grained rock, It is One of the Oldest, Strongest and Hardest Rock
Archaeological Significance
Monuments
Used
Not Yet Used
Famous Monuments
Konark Sun Temple in India, Washington Monument, US
Not Applicable
Sculpture
Not Yet Used
Not Yet Used
Famous Sculptures
Not Applicable
Not Applicable
Pictographs
Not Used
Not Used
Petroglyphs
Not Used
Not Used
Figurines
Not Yet Used
Not Yet Used
Formation
Gneiss is a high grade metamorphic rock i.e. it has been subjected to higher temperatures and pressures than schist. It is formed by the metamorphosis of Gneiss forms from volcanic rock, shale or granitie.
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
Biotite, Chlorite, Feldspar, Garnet, Graphite, Hornblade, Micas, Muscovite or Illite, Quartz, Quartzite, Silica, Zircon
Albite, Amphibole, Quartz
Compound Content
Aluminium Oxide, NaCl, CaO, Iron(III) Oxide, FeO, Potassium Oxide, Magnesium Carbonate, MgO, MnO, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Al, Fe, Potassium Oxide
Types of Metamorphism
Impact Metamorphism
Cataclastic Metamorphism, Regional Metamorphism
Types of Weathering
Biological Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Sea Erosion
Coastal Erosion, Water Erosion
Grain Size
Medium to Coarse Grained
Medium Grained
Fracture
Irregular
Pervasive
Streak
White
Bluish Black
Porosity
Very Less Porous
Highly Porous
Cleavage
Poor
Not Available
Specific Gravity
2.5-2.7
2.38
Transparency
Translucent to Opaque
Opaque
Density
2.6-2.9 g/cm3
Not Available
Resistance
Heat Resistant, Pressure Resistant, Scratch Resistant, Wear Resistant
Heat Resistant, Impact Resistant
Deposits in Eastern Continents
Asia
China, India, Iran, Iraq, Kazakhstan, Kyrgyzstan, Mongolia, Russia
China
Africa
Cameroon, Ethiopia, Ghana, Kenya, Madagascar, Morocco, Mozambique, Namibia, Nigeria, Tanzania, Togo
East Africa
Europe
Albania, Austria, Bosnia and Herzegovina, Finland, France, Georgia, Germany, Hungary, Italy, Kosovo, Monaco, Norway, Poland, Romania, Serbia, Slovakia, Slovenia, Switzerland, Ukraine, United Kingdom
Italy
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
Canada, Costa Rica, Cuba, Mexico, Panama, USA
Not Yet Found
South America
Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Peru, Venezuela
Not Yet Found
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Queensland, Victoria
Queensland
Gneiss vs Comendite 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. Gneiss vs Comendite characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Gneiss and Properties of Comendite. Learn more about Gneiss vs Comendite in the next section. The interior uses of Gneiss include Countertops, Decorative aggregates, Flooring and Interior decoration whereas the interior uses of Comendite include Countertops, Decorative aggregates and Interior decoration. Due to some exceptional properties of Gneiss and Comendite, they have various applications in construction industry. The uses of Gneiss in construction industry include As dimension stone and that of Comendite include Building houses or walls, Cement manufacture, Construction aggregate, For road aggregate, Landscaping, Making natural cement, Raw material for the manufacture of mortar.
More about Gneiss and Comendite
Here you can know more about Gneiss and Comendite. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Gneiss and Comendite consists of mineral content and compound content. The mineral content of Gneiss includes Biotite, Chlorite, Feldspar, Garnet, Graphite, Hornblade, Micas, Muscovite or Illite, Quartz, Quartzite, Silica, Zircon and mineral content of Comendite includes Albite, Amphibole, Quartz. You can also check out the list of all Metamorphic Rocks. When we have to compare Gneiss vs Comendite, the texture, color and appearance plays an important role in determining the type of rock. Gneiss is available in black, brown, pink, red, white colors whereas, Comendite is available in blue, bluish - grey colors. Appearance of Gneiss is Foliated and that of Comendite is Foliated. Properties of rock is another aspect for Gneiss vs Comendite. The hardness of Gneiss is 7 and that of Comendite is 6-7. The types of Gneiss are Augen Gneiss, Henderson Gneiss, Lewisian Gneiss, Archean and Proterozoic Gneiss. whereas types of Comendite are Rhyolite. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Gneiss is white while that of Comendite is bluish black. The specific heat capacity of Gneiss is Not Available and that of Comendite is Not Available. Depending on the properties like hardness, toughness, specific heat capacity, porosity etc., rocks are resistant to heat, wear, impact, etc.Gneiss is heat resistant, pressure resistant, scratch resistant, wear resistant whereas Comendite is heat resistant, impact resistant.