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
Granite is a very hard, granular, crystalline igneous rock which consists mainly of quartz, mica, and feldspar and is often used as building stone
Discoverer
Unknown
Alexander von Humboldt
Etymology
From the Middle High German verb gneist (to spark; so called because the rock glitters)
From Italian granito, which means grained rock, from grano grain, and from Latin granum
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
Granular, Phaneritic
Color
Black, Brown, Pink, Red, White
Black, Grey, Orange, Pink, White
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Foliated
Veined or Pebbled
Interior Uses
Countertops, Decorative Aggregates, Flooring, Interior Decoration
Countertops, Decorative Aggregates, Entryways, Floor Tiles, Flooring, Homes, Hotels, Interior Decoration, Kitchens, Stair Treads
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
As Building Stone, As Facing Stone, Bridges, Paving Stone, Garden Decoration, Near Swimming Pools, Office Buildings, Resorts
Other Architectural Uses
Curbing
Curbing
Construction Industry
As Dimension Stone
As Dimension Stone
Antiquity Uses
Artifacts
Monuments, Sculpture, Small Figurines
Commercial Uses
Cemetery Markers, Jewelry, Tombstones, Used in aquariums
Curling, Gemstone, Laboratory bench tops, Tombstones, Used in aquariums
Types
Augen Gneiss, Henderson Gneiss, Lewisian Gneiss, Archean and Proterozoic Gneiss.
Igneous Protolith Granite, Sedimentary Protolith Granite, Mantle Granite, Anorogenic Granite, Hybrid Granite, Granodiorite and Alkali Feldspar Granite
Features
Generally rough to touch, Is one of the oldest rock
Available in Lots of Colors and Patterns, It is One of the Oldest, Strongest and Hardest Rock
Archaeological Significance
Famous Monuments
Konark Sun Temple in India, Washington Monument, US
Agia Sophia in Istanbul, Turkey, Blue Domed Church in Santorini, Greece, Blue Mosque in Istanbul, Charminar in Hyderabad, India, Diana, Princess of Wales Memorial Fountain in London, UK, Ephesus in Turkey, Georgia Guidestones in Georgia, US, Hermitage in Saint Petersburg, Khajuraho Temples, India, Mahabalipuram in Tamil Nadu, India, Mysore Palace in Karnataka, India, Signers Monument in Augusta, Georgia, Statue of Liberty in New York, USA, Taj Mahal in Agra, India, Tower Bridge in London, Vietnam Veterans Memorial in Washington, US, Washington Monument, US
Famous Sculptures
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Avukana Buddha Statue in Sri Lanka, Lincoln Memorial in America, Mount Rushmore National Memorial in South Dakota, US, The Colossal Red Granite Statue of Amenhotep III in Karnak, Egypt
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.
Granite is an intrusive igneous rock which is very hard, crystalline and is visibly homogeneous in texture and forms by melting of continental rocks
Mineral Content
Biotite, Chlorite, Feldspar, Garnet, Graphite, Hornblade, Micas, Muscovite or Illite, Quartz, Quartzite, Silica, Zircon
Amphibole, Biotite, Feldspar, Hornblade, Micas, Muscovite or Illite, Plagioclase, Pyroxene, Quartz
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, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Types of Metamorphism
Impact Metamorphism
Burial Metamorphism, Cataclastic Metamorphism
Types of Weathering
Biological Weathering, Mechanical Weathering
Biological Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Sea Erosion
Chemical Erosion, Sea Erosion, Water Erosion
Grain Size
Medium to Coarse Grained
Large and Coarse Grained
Porosity
Very Less Porous
Less Porous
Luster
Dull
Dull to Grainy with Sporadic parts Pearly and Vitreous
Specific Gravity
2.5-2.7
2.6-2.7
Transparency
Translucent to Opaque
Opaque
Density
2.6-2.9 g/cm3
2.65-2.75 g/cm3
Resistance
Heat Resistant, Pressure Resistant, Scratch Resistant, Wear Resistant
Heat Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
China, India, Iran, Iraq, Kazakhstan, Kyrgyzstan, Mongolia, Russia
China, India, Iran, Saudi Arabia, Sri Lanka, Taiwan, Thailand, Turkey, Vietnam
Africa
Cameroon, Ethiopia, Ghana, Kenya, Madagascar, Morocco, Mozambique, Namibia, Nigeria, Tanzania, Togo
Angola, Egypt, Madagascar, Namibia, Nigeria, 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
Austria, Belgium, Finland, France, Germany, Italy, Norway, Sardinia, Spain, Switzerland, The Czech Republic
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
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Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Queensland, Victoria
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