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
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers called coal beds
History
Origin
-
USA
Discoverer
Unknown
John Peter Salley
Etymology
From the Middle High German verb gneist (to spark; so called because the rock glitters)
From the Old English term col, which has meant mineral of fossilized carbon since the 13th century
Class
Metamorphic Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Soft Rock
Family
Group
-
-
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
Amorphous, Glassy
Color
Black, Brown, Pink, Red, White
Black, Brown, Dark Brown, Grey, Light to Dark Grey
Maintenance
More
Less
Durability
Durable
Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Foliated
Veined or Pebbled
Architecture
Interior Uses
Countertops, Decorative Aggregates, Flooring, Interior Decoration
-
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
-
Other Architectural Uses
Curbing
-
Industry
Construction Industry
As Dimension Stone
Cement Manufacture, for Road Aggregate, Making natural cement, Steel Production
Medical Industry
-
-
Antiquity Uses
Artifacts
Artifacts
Other Uses
Commercial Uses
Cemetery Markers, Jewelry, Tombstones, Used in aquariums
Alumina Refineries, Electricity Generation, Liquid Fuel, Manufacture of Soap, Solvents, Dyes, Plastics and Fibres, Paper Industry
Types
Augen Gneiss, Henderson Gneiss, Lewisian Gneiss, Archean and Proterozoic Gneiss.
Peat, Lignite, Sub-Bituminous Coal, Bituminous Coal, Anthracite, Graphite
Features
Generally rough to touch, Is one of the oldest rock
Helps in production of Heat and Electricity, Used as fossil fuel
Archaeological Significance
Monuments
-
-
Famous Monuments
Konark Sun Temple in India, Washington Monument, US
-
Sculpture
-
-
Famous Sculptures
-
-
Pictographs
-
-
Petroglyphs
-
-
Figurines
-
-
Fossils
Absent
Present
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.
Coal forms from the accumulation of plant debris in a swamp environment which is buried by sediments such as mud or sand and then compacted to form coal.
Composition
Mineral Content
Biotite, Chlorite, Feldspar, Garnet, Graphite, Hornblade, Micas, Muscovite or Illite, Quartz, Quartzite, Silica, Zircon
Analcime, Apatite, Barite, Calcite, Chalcopyrite, Chlorite, Chromite, Clausthalite, Clay Minerals, Crandallite Group, Dolomite, Feldspar, Galena, Gypsum, Marcasite, Muscovite or Illite, Pyrite, Quartz, Siderite, Sphalerite, Zircon
Compound Content
Aluminium Oxide, NaCl, CaO, Iron(III) Oxide, FeO, Potassium Oxide, Magnesium Carbonate, MgO, MnO, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Carbon, Hydrogen, Nitrogen, Oxygen, Sulphur
Transformation
Metamorphism
✔
✘
✔
✘
Types of Metamorphism
Impact Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism
Weathering
✔
✘
✔
✘
Types of Weathering
Biological Weathering, Mechanical Weathering
-
Erosion
✔
✘
✔
✘
Types of Erosion
Chemical Erosion, Coastal Erosion, Sea Erosion
-
Physical Properties
Hardness
71-1.5
1
7
👆🏻
Grain Size
Medium to Coarse Grained
Medium to Fine Coarse Grained
Fracture
Irregular
Conchoidal
Streak
White
Black
Porosity
Very Less Porous
Less Porous
Luster
Dull
Dull to Vitreous to Submetallic
Compressive Strength
125.00 N/mm2-
0.15
450
👆🏻
Cleavage
-
-
Toughness
1.2
-
Specific Gravity
2.5-2.71.1-1.4
0
8.4
👆🏻
Transparency
Translucent to Opaque
Opaque
Density
2.6-2.9 g/cm31100-1400 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
0.70 kJ/Kg K1.32 kJ/Kg K
0.14
3.2
👆🏻
Resistance
Heat Resistant, Pressure Resistant, Scratch Resistant, Wear Resistant
Heat Resistant
Deposits in Eastern Continents
Asia
China, India, Iran, Iraq, Kazakhstan, Kyrgyzstan, Mongolia, Russia
Bangladesh, Burma, Cambodia, China, India, Indonesia, Kazakhstan, Malaysia, Mongolia, Pakistan, Turkey, Vietnam
Africa
Cameroon, Ethiopia, Ghana, Kenya, Madagascar, Morocco, Mozambique, Namibia, Nigeria, Tanzania, Togo
Botswana, Kenya, Morocco, Mozambique, South Africa, Tanzania
Europe
Albania, Austria, Bosnia and Herzegovina, Finland, France, Georgia, Germany, Hungary, Italy, Kosovo, Monaco, Norway, Poland, Romania, Serbia, Slovakia, Slovenia, Switzerland, Ukraine, United Kingdom
Belgium, Bulgaria, England, France, Germany, Greece, Hungary, Kosovo, Netherlands, Norway, Poland, Romania, Serbia, Slovakia, Slovenia, The Czech Republic, Ukraine, United Kingdom
Others
-
-
Deposits in Western Continents
North America
Canada, Costa Rica, Cuba, Mexico, Panama, USA
Canada, Mexico, USA
South America
Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Peru, Venezuela
Brazil, Chile, Colombia, Venezuela
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Queensland, Victoria
New South Wales, Queensland, Victoria