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
Adakite is an intermediate to felsic volcanic rock that has geochemical characteristics of magma which is said to be formed by partial melting of altered basalt that is subducted below volcanic arcs
Origin
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Adak, Aleutian Islands
Discoverer
Unknown
Defant and Drummond
Etymology
From the Middle High German verb gneist (to spark; so called because the rock glitters)
From Adak, Aleutian Islands
Class
Metamorphic Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Other Categories
Coarse Grained Rock, Medium Grained Rock, Opaque Rock
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Banded, Foliated, Platy
Porphyritic
Color
Black, Brown, Pink, Red, White
Black, Brown, Light to Dark Grey
Durability
Durable
Durable
Appearance
Foliated
Dull and Soft
Interior Uses
Countertops, Decorative Aggregates, Flooring, Interior Decoration
Decorative Aggregates, Floor Tiles, Homes, Hotels, Kitchens
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
As Building Stone, As Facing Stone, Office Buildings
Other Architectural Uses
Curbing
Whetstones
Construction Industry
As Dimension Stone
As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone
Antiquity Uses
Artifacts
Monuments, Sculpture, Small Figurines
Commercial Uses
Cemetery Markers, Jewelry, Tombstones, Used in aquariums
Commemorative Tablets, Pottery, Used in aquariums
Types
Augen Gneiss, Henderson Gneiss, Lewisian Gneiss, Archean and Proterozoic Gneiss.
Intermediate volcanic rock
Features
Generally rough to touch, Is one of the oldest rock
Has High structural resistance against erosion and climate, Host rock for Diamond, Very fine grained rock
Archaeological Significance
Famous Monuments
Konark Sun Temple in India, Washington Monument, US
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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.
Adakite rocks are formed when the hydrous fluids are released from minerals that break down in metamorphosed basalt, and rise into the mantle they initiate partial melting.
Mineral Content
Biotite, Chlorite, Feldspar, Garnet, Graphite, Hornblade, Micas, Muscovite or Illite, Quartz, Quartzite, Silica, Zircon
Olivine, Plagioclase, Pyroxene
Compound Content
Aluminium Oxide, NaCl, CaO, Iron(III) Oxide, FeO, Potassium Oxide, Magnesium Carbonate, MgO, MnO, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Aluminium Oxide, MgO, Silicon Dioxide
Types of Metamorphism
Impact Metamorphism
Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism
Types of Weathering
Biological Weathering, Mechanical Weathering
Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Sea Erosion
Coastal Erosion, Sea Erosion, Water Erosion
Grain Size
Medium to Coarse Grained
Fine to Medium Grained
Fracture
Irregular
Conchoidal
Streak
White
Bluish Black
Porosity
Very Less Porous
Less Porous
Luster
Dull
Grainy, Pearly and Vitreous
Specific Gravity
2.5-2.7
-9999
Transparency
Translucent to Opaque
Opaque
Density
2.6-2.9 g/cm3
-9999 g/cm3
Resistance
Heat Resistant, Pressure Resistant, Scratch Resistant, Wear Resistant
Heat Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
China, India, Iran, Iraq, Kazakhstan, Kyrgyzstan, Mongolia, Russia
India, Russia
Africa
Cameroon, Ethiopia, Ghana, Kenya, Madagascar, Morocco, Mozambique, Namibia, Nigeria, Tanzania, Togo
Ethiopia, Somalia, South 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
Iceland
Deposits in Western Continents
North America
Canada, Costa Rica, Cuba, Mexico, Panama, USA
Canada, USA
South America
Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Peru, Venezuela
Brazil
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Queensland, Victoria
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Gneiss vs Adakite 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 Adakite characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Gneiss and Properties of Adakite. Learn more about Gneiss vs Adakite in the next section. The interior uses of Gneiss include Countertops, Decorative aggregates, Flooring and Interior decoration whereas the interior uses of Adakite include Decorative aggregates, Floor tiles, Homes, Hotels and Kitchens. Due to some exceptional properties of Gneiss and Adakite, they have various applications in construction industry. The uses of Gneiss in construction industry include As dimension stone and that of Adakite include As dimension stone, Cobblestones, Rail track ballast, Roadstone.
More about Gneiss and Adakite
Here you can know more about Gneiss and Adakite. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Gneiss and Adakite 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 Adakite includes Olivine, Plagioclase, Pyroxene. You can also check out the list of all Metamorphic Rocks. When we have to compare Gneiss vs Adakite, 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, Adakite is available in black, brown, light to dark grey colors. Appearance of Gneiss is Foliated and that of Adakite is Dull and Soft. Properties of rock is another aspect for Gneiss vs Adakite. The hardness of Gneiss is 7 and that of Adakite is 3-4. The types of Gneiss are Augen Gneiss, Henderson Gneiss, Lewisian Gneiss, Archean and Proterozoic Gneiss. whereas types of Adakite are Intermediate volcanic rock. 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 Adakite is bluish black. The specific heat capacity of Gneiss is 0.70 kJ/Kg K and that of Adakite 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.Gneiss is heat resistant, pressure resistant, scratch resistant, wear resistant whereas Adakite is heat resistant, pressure resistant, wear resistant.