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
Diatomite is a fine-grained sedimentary rock which is formed from consolidated diatomaceous earth
History
Origin
-
Germany
Discoverer
Unknown
Unknown
Etymology
From the Middle High German verb gneist (to spark; so called because the rock glitters)
From diatom + -ite1
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
Fine Grained Rock, Opaque Rock
Texture
Banded, Foliated, Platy
Clastic or Non-Clastic
Color
Black, Brown, Pink, Red, White
Grey, White, Yellow
Maintenance
More
Less
Durability
Durable
Non-Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Foliated
Soft
Architecture
Interior Uses
Countertops, Decorative Aggregates, Flooring, Interior Decoration
Decorative Aggregates, Homes, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
Garden Decoration, Paving Stone
Other Architectural Uses
Curbing
Curbing
Industry
Construction Industry
As Dimension Stone
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate, Landscaping, Making natural cement, Source of calcium
Medical Industry
-
-
Antiquity Uses
Artifacts
Artifacts
Other Uses
Commercial Uses
Cemetery Markers, Jewelry, Tombstones, Used in aquariums
Alumina Refineries, Animal feed filler, As a Feed Additive for Livestock, Creating Artwork, Drawing on blackboards, Fire resistant, Gymnasts, athletes and mountain climbers use for grip, In aquifers, Soil Conditioner, To ignite fire, Used as a filter medium, Used as an insecticide, Whiting material in toothpaste, paint and paper
Types
Augen Gneiss, Henderson Gneiss, Lewisian Gneiss, Archean and Proterozoic Gneiss.
Diatomite
Features
Generally rough to touch, Is one of the oldest rock
Clasts are smooth to touch, Is one of the oldest rock, Smooth to touch, Very fine grained rock
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.
Diatomite rock formed from the skeletal remains of single celled plants called diatoms. When diatoms die, their skeletal remains sink to the bottom of lakes and oceans etc. hence forming diatomite deposit.
Composition
Mineral Content
Biotite, Chlorite, Feldspar, Garnet, Graphite, Hornblade, Micas, Muscovite or Illite, Quartz, Quartzite, Silica, Zircon
Calcite, Clay, Clay Minerals, Quartz, Sand
Compound Content
Aluminium Oxide, NaCl, CaO, Iron(III) Oxide, FeO, Potassium Oxide, Magnesium Carbonate, MgO, MnO, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Ca, NaCl, CaO
Transformation
Metamorphism
✔
✘
✔
✘
Types of Metamorphism
Impact Metamorphism
-
Weathering
✔
✘
✔
✘
Types of Weathering
Biological Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Erosion
✔
✘
✔
✘
Types of Erosion
Chemical Erosion, Coastal Erosion, Sea Erosion
Chemical Erosion, Coastal Erosion, Wind Erosion
Physical Properties
Hardness
71
1
7
👆🏻
Grain Size
Medium to Coarse Grained
Very fine-grained
Fracture
Irregular
-
Streak
White
White
Porosity
Very Less Porous
Highly Porous
Luster
Dull
Dull
Compressive Strength
125.00 N/mm2-
0.15
450
👆🏻
Cleavage
-
-
Toughness
1.2
1
Specific Gravity
2.5-2.72.3-2.4
0
8.4
👆🏻
Transparency
Translucent to Opaque
Opaque
Density
2.6-2.9 g/cm32.49-2.51 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
0.70 kJ/Kg K0.90 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
Brunei, India, Indonesia, Malaysia, Singapore, Thailand, Vietnam
Africa
Cameroon, Ethiopia, Ghana, Kenya, Madagascar, Morocco, Mozambique, Namibia, Nigeria, Tanzania, Togo
Cameroon, Chad, Ghana, Kenya, Malawi, Sudan, Tanzania, Togo, Zambia, Zimbabwe
Europe
Albania, Austria, Bosnia and Herzegovina, Finland, France, Georgia, Germany, Hungary, Italy, Kosovo, Monaco, Norway, Poland, Romania, Serbia, Slovakia, Slovenia, Switzerland, Ukraine, United Kingdom
England, France, Germany, Spain, United Kingdom
Others
-
-
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
Colombia
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Queensland, Victoria
Adelaide, New Zealand, Queensland, Victoria, Yorke Peninsula