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
Carbonatite is intrusive or extrusive igneous rock which is defined by mineralogic composition, consisting of greater than 50 percent carbonate minerals
Discoverer
Unknown
Unknown
Etymology
From the Middle High German verb gneist (to spark; so called because the rock glitters)
From any intrusive igneous rock, having a majority of carbonate minerals
Class
Metamorphic Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Soft Rock
Group
Not Applicable
Plutonic
Other Categories
Coarse Grained Rock, Medium Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Banded, Foliated, Platy
Granular, Poikiloblastic
Color
Black, Brown, Pink, Red, White
Black, Brown, Colourless, Green, Grey, Pink, White
Durability
Durable
Durable
Appearance
Foliated
Dull, Banded and Foilated
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 Facing Stone, Garden Decoration
Other Architectural Uses
Curbing
Curbing
Construction Industry
As Dimension Stone
As a Flux in the Production of Steel and Pig Iron, As a Sintering Agent in Steel Industry to process Iron Ore, As Dimension Stone, Cement Manufacture, for Road Aggregate, Making natural cement, Manufacture of Magnesium and Dolomite Refractories, Unknown, Unknown
Medical Industry
Not Yet Used
Taken as a Supplement for Calcium or Magnesium
Antiquity Uses
Artifacts
Artifacts
Commercial Uses
Cemetery Markers, Jewelry, Tombstones, Used in aquariums
An Oil and Gas Reservoir, As a Feed Additive for Livestock, Gemstone, Metallurgical Flux
Types
Augen Gneiss, Henderson Gneiss, Lewisian Gneiss, Archean and Proterozoic Gneiss.
Not Available
Features
Generally rough to touch, Is one of the oldest rock
Available in lots of colors, Generally rough to touch, Is one of the oldest 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
Used
Petroglyphs
Not Used
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.
Carbonatites are intrusive or extrusive igneous rocks which are defined by mineralogic composition consisting of greater than 50 percent carbonate minerals and are formed due to low degrees of partial melting of rocks.
Mineral Content
Biotite, Chlorite, Feldspar, Garnet, Graphite, Hornblade, Micas, Muscovite or Illite, Quartz, Quartzite, Silica, Zircon
Ancylite, Apatite, Barite, Fluorite, Magnetite, Natrolite, Sodalite
Compound Content
Aluminium Oxide, NaCl, CaO, Iron(III) Oxide, FeO, Potassium Oxide, Magnesium Carbonate, MgO, MnO, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
CaO, Carbon Dioxide, Sodium Oxide
Types of Metamorphism
Impact Metamorphism
Burial Metamorphism, Contact 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, Wind Erosion
Grain Size
Medium to Coarse Grained
Medium to Fine Coarse Grained
Fracture
Irregular
Conchoidal
Porosity
Very Less Porous
Less Porous
Luster
Dull
Subvitreous to Dull
Compressive Strength
Not Available
Cleavage
Poor
Not Available
Specific Gravity
2.5-2.7
2.86-2.87
Transparency
Translucent to Opaque
Opaque
Density
2.6-2.9 g/cm3
2.84-2.86 g/cm3
Resistance
Heat Resistant, Pressure Resistant, Scratch Resistant, Wear Resistant
Heat Resistant, Pressure Resistant, Water Resistant
Deposits in Eastern Continents
Asia
China, India, Iran, Iraq, Kazakhstan, Kyrgyzstan, Mongolia, Russia
China, India, Kazakhstan, Mongolia, Russia, Uzbekistan
Africa
Cameroon, Ethiopia, Ghana, Kenya, Madagascar, Morocco, Mozambique, Namibia, Nigeria, Tanzania, Togo
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, Denmark, Germany, Great Britain, Netherlands, Norway, Poland, Sweden, Switzerland, United Kingdom
Others
Not Yet Found
Greenland
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 South Wales, New Zealand