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
Gabbro is an intrusive igneous rock which is chemically equivalent to plutonic Basalt
Discoverer
Unknown
Christian Leopold von Buch
Etymology
From the Middle High German verb gneist (to spark; so called because the rock glitters)
From Latin glaber bare, smooth, bald
Class
Metamorphic Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
Other Categories
Coarse Grained Rock, Medium Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock
Texture
Banded, Foliated, Platy
Phaneritic
Color
Black, Brown, Pink, Red, White
Dark Grey to Black
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Foliated
Veined and Shiny
Interior Uses
Countertops, Decorative Aggregates, Flooring, Interior Decoration
Countertops, Decorative Aggregates, Homes, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
Other Architectural Uses
Curbing
Curbing
Construction Industry
As Dimension Stone
As Dimension Stone, Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate
Antiquity Uses
Artifacts
Artifacts, Monuments, Sculpture
Commercial Uses
Cemetery Markers, Jewelry, Tombstones, Used in aquariums
Cemetery Markers, Commemorative Tablets, Laboratory bench tops, Jewelry, Sea Defence, Tombstones
Types
Augen Gneiss, Henderson Gneiss, Lewisian Gneiss, Archean and Proterozoic Gneiss.
Anorthosite Gabbro and Norite Gabbro
Features
Generally rough to touch, Is one of the oldest rock
Smooth to touch
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.
Gabbro, a mafic rock, forms due to cooling and crystallization of magma underneath Earth's surface.
Mineral Content
Biotite, Chlorite, Feldspar, Garnet, Graphite, Hornblade, Micas, Muscovite or Illite, Quartz, Quartzite, Silica, Zircon
Augite, 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, CaO, Chromium(III) Oxide, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Sulfur Trioxide
Types of Metamorphism
Impact Metamorphism
Impact Metamorphism
Types of Weathering
Biological Weathering, Mechanical Weathering
Chemical Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Sea Erosion
Coastal Erosion
Grain Size
Medium to Coarse Grained
Coarse Grained
Fracture
Irregular
Conchoidal
Porosity
Very Less Porous
Highly Porous
Specific Gravity
2.5-2.7
2.86-2.87
Transparency
Translucent to Opaque
Opaque
Density
2.6-2.9 g/cm3
2.7-3.3 g/cm3
Resistance
Heat Resistant, Pressure Resistant, Scratch Resistant, Wear Resistant
Impact 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
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
Germany, Greece, Italy, Scotland, Turkey
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, Colombia, Venezuela
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Queensland, Victoria
New Zealand, Queensland
Gneiss vs Gabbro 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 Gabbro characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Gneiss and Properties of Gabbro. Learn more about Gneiss vs Gabbro in the next section. The interior uses of Gneiss include Countertops, Decorative aggregates, Flooring and Interior decoration whereas the interior uses of Gabbro include Countertops, Decorative aggregates, Homes and Interior decoration. Due to some exceptional properties of Gneiss and Gabbro, they have various applications in construction industry. The uses of Gneiss in construction industry include As dimension stone and that of Gabbro include As dimension stone, Building houses or walls, Cement manufacture, Construction aggregate, For road aggregate.
More about Gneiss and Gabbro
Here you can know more about Gneiss and Gabbro. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Gneiss and Gabbro 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 Gabbro includes Augite, Olivine, Plagioclase, Pyroxene. You can also check out the list of all Metamorphic Rocks. When we have to compare Gneiss vs Gabbro, 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, Gabbro is available in dark grey to black colors. Appearance of Gneiss is Foliated and that of Gabbro is Veined and Shiny. Properties of rock is another aspect for Gneiss vs Gabbro. Hardness of Gneiss and Gabbro is 7. The types of Gneiss are Augen Gneiss, Henderson Gneiss, Lewisian Gneiss, Archean and Proterozoic Gneiss. whereas types of Gabbro are Anorthosite Gabbro and Norite Gabbro. 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 Gabbro is black. The specific heat capacity of Gneiss is 0.70 kJ/Kg K and that of Gabbro is 0.71 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 Gabbro is impact resistant, pressure resistant, wear resistant.