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
Peridotite is a dense, coarse-grained plutonic is the main constituent of the earth's mantle
Origin
-
Pike County, U.S
Discoverer
Unknown
Unknown
Etymology
From the Middle High German verb gneist (to spark; so called because the rock glitters)
From French, from peridot + -ite
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
Coarse Grained Rock, Opaque Rock
Texture
Banded, Foliated, Platy
Phaneritic
Color
Black, Brown, Pink, Red, White
Dark Greenish - Grey
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Foliated
Rough and Shiny
Interior Uses
Countertops, Decorative Aggregates, Flooring, Interior Decoration
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
As Dimension Stone, Cobblestones
Antiquity Uses
Artifacts
Monuments, Sculpture, Small Figurines
Commercial Uses
Cemetery Markers, Jewelry, Tombstones, Used in aquariums
Creating Artwork, Gemstone, Jewelry, Source of Chromite, Platinum, Nickel and Garnet, Source of Diamonds
Types
Augen Gneiss, Henderson Gneiss, Lewisian Gneiss, Archean and Proterozoic Gneiss.
Dunite, Wehrlite, Harzburgite, Lherzolite and Pyrolite
Features
Generally rough to touch, Is one of the oldest rock
Constitutes upper part of the Earth's mantle, Generally rough to touch, Host rock for Diamond, Is one of the oldest 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.
Peridotites can be formed in two ways: as mantle rocks formed during the accretion and differentiation of the Earth or as cumulate rocks formed by precipitation of olivine and pyroxenes from basaltic magmas.
Mineral Content
Biotite, Chlorite, Feldspar, Garnet, Graphite, Hornblade, Micas, Muscovite or Illite, Quartz, Quartzite, Silica, Zircon
Amphibole, Chromite, Garnet, Magnesium, Olivine, Phlogopite, Plagioclase, Pyroxene
Compound Content
Aluminium Oxide, NaCl, CaO, Iron(III) Oxide, FeO, Potassium Oxide, Magnesium Carbonate, MgO, MnO, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Ca, Fe, Mg, Potassium, Silicon Dioxide, Sodium, Titanium Dioxide
Types of Metamorphism
Impact Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact 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
Chemical Erosion
Grain Size
Medium to Coarse Grained
Coarse Grained
Fracture
Irregular
Irregular
Porosity
Very Less Porous
Less Porous
Specific Gravity
2.5-2.7
3-3.01
Transparency
Translucent to Opaque
Translucent to Opaque
Density
2.6-2.9 g/cm3
3.1-3.4 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
China, India, Indonesia, Kazakhstan, Russia, South Korea, Thailand, Turkey
Africa
Cameroon, Ethiopia, Ghana, Kenya, Madagascar, Morocco, Mozambique, Namibia, Nigeria, Tanzania, Togo
Morocco, 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
Finland, France, Georgia, Germany, Great Britain, Italy, Kazakhstan, Netherlands, Norway, Spain, Switzerland
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
New Zealand, Western Australia
Gneiss vs Peridotite 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 Peridotite characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Gneiss and Properties of Peridotite. Learn more about Gneiss vs Peridotite in the next section. The interior uses of Gneiss include Countertops, Decorative aggregates, Flooring and Interior decoration whereas the interior uses of Peridotite include Decorative aggregates and Interior decoration. Due to some exceptional properties of Gneiss and Peridotite, they have various applications in construction industry. The uses of Gneiss in construction industry include As dimension stone and that of Peridotite include As dimension stone, Cobblestones.
More about Gneiss and Peridotite
Here you can know more about Gneiss and Peridotite. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Gneiss and Peridotite 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 Peridotite includes Amphibole, Chromite, Garnet, Magnesium, Olivine, Phlogopite, Plagioclase, Pyroxene. You can also check out the list of all Metamorphic Rocks. When we have to compare Gneiss vs Peridotite, 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, Peridotite is available in dark greenish - grey colors. Appearance of Gneiss is Foliated and that of Peridotite is Rough and Shiny. Properties of rock is another aspect for Gneiss vs Peridotite. The hardness of Gneiss is 7 and that of Peridotite is 5.5-6. The types of Gneiss are Augen Gneiss, Henderson Gneiss, Lewisian Gneiss, Archean and Proterozoic Gneiss. whereas types of Peridotite are Dunite, Wehrlite, Harzburgite, Lherzolite and Pyrolite. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Gneiss and Peridotite is white. The specific heat capacity of Gneiss is 0.70 kJ/Kg K and that of Peridotite is 1.26 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 Peridotite is heat resistant, pressure resistant, wear resistant.