Definition
Gritstone or grit is a hard, coarse-grained, siliceous sandstone
  
Picrite is a variety of high-magnesium olivine basalt that is very rich in the mineral olivine
  
History
  
  
Origin
Pennines, England
  
Hawaii Islands
  
Discoverer
J.J. Ferber
  
Unknown
  
Etymology
From Grit + Stone
  
From Greek pikros bitter + -ite, 19th century
  
Class
Sedimentary Rocks
  
Igneous Rocks
  
Sub-Class
Durable Rock, Hard Rock
  
Durable Rock, Hard Rock
  
Family
  
  
Group
Not Applicable
  
Volcanic
  
Other Categories
Coarse Grained Rock, Opaque Rock
  
Fine Grained Rock, Opaque Rock
  
Texture
Earthy
  
Earthy, Rough
  
Color
Beige, Black, Brown, Colourless, Cream, Dark Brown, Green, Grey, Light Green, Light to Dark Grey, Pink, Red, White, Yellow
  
Black, Brown, Colourless, Green, Grey, Pink, White, Yellow
  
Maintenance
Less
  
Less
  
Durability
Durable
  
Durable
  
Water Resistant
Yes
  
Yes
  
Scratch Resistant
Yes
  
Yes
  
Stain Resistant
Yes
  
Yes
  
Wind Resistant
Yes
  
Yes
  
Acid Resistant
No
  
Yes
  
Appearance
Layered and Foliated
  
Rough and Shiny
  
Architecture
  
  
Interior Uses
Countertops, Decorative Aggregates, Homes, Interior Decoration
  
Countertops, Decorative Aggregates, Homes, Interior Decoration
  
Exterior Uses
As Building Stone, Garden Decoration, Office Buildings, Paving Stone
  
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
  
Other Architectural Uses
Curbing
  
Curbing
  
Industry
  
  
Construction Industry
Construction Aggregate, Roadstone
  
As a Sintering Agent in Steel Industry to process Iron Ore, Cement Manufacture, for Road Aggregate, Manufacture of Magnesium and Dolomite Refractories, Roadstone, Used for flooring, stair treads, borders and window sills.
  
Medical Industry
Not Yet Used
  
Not Yet Used
  
Antiquity Uses
Artifacts, Monuments, Sculpture
  
Artifacts, Monuments, Sculpture
  
Other Uses
  
  
Commercial Uses
An Oil and Gas Reservoir, As a Feed Additive for Livestock, Gemstone, Metallurgical Flux, Production of Lime, Soil Conditioner, Source of Magnesia (MgO), Tombstones
  
As a Feed Additive for Livestock, As armour rock for sea walls, Metallurgical Flux, Pottery, Source of Magnesia (MgO)
  
Types
Not Available
  
Oceanite
  
Features
Available in Lots of Colors and Patterns, Generally rough to touch, Very fine grained rock
  
Host Rock for Lead
  
Archaeological Significance
  
  
Monuments
Used
  
Used
  
Famous Monuments
Data Not Available
  
Data Not Available
  
Sculpture
Used
  
Used
  
Famous Sculptures
Data Not Available
  
Data Not Available
  
Pictographs
Not Used
  
Not Used
  
Petroglyphs
Not Used
  
Not Used
  
Figurines
Used
  
Used
  
Fossils
Present
  
Absent
  
Formation
Gritstone is a type of sedimentary rock which was formed on the floors of wide river deltas where the grit deposits were laid down, with every tide or flood dumping another layer of sediment.
  
Picrite is a fine-grained, hard rock which is a type of metasomatite, essentially altered basalt. It forms with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.
  
Composition
  
  
Mineral Content
Calcite, Clay Minerals, Feldspar, Micas, Quartz
  
Biotite, Olivine, Plagioclase, Pyrrhotite
  
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide
  
Al, CaO, Carbon Dioxide, Mg, MgO
  
Transformation
  
  
Metamorphism
No
  
Yes
  
Types of Metamorphism
Not Applicable
  
Burial Metamorphism, Cataclastic Metamorphism, Impact Metamorphism, Regional Metamorphism
  
Weathering
Yes
  
Yes
  
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
  
Biological Weathering
  
Erosion
Yes
  
Yes
  
Types of Erosion
Chemical Erosion, Coastal Erosion
  
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
  
Physical Properties
  
  
Hardness
6-7
  
6.8
  
Grain Size
Coarse Grained
  
Fine Grained
  
Fracture
Conchoidal
  
Uneven
  
Streak
White
  
White, Greenish White or Grey
  
Porosity
Highly Porous
  
Less Porous
  
Luster
Dull
  
Subvitreous to Dull
  
Compressive Strength
70.00 N/mm2
  
24
189.00 N/mm2
  
11
Cleavage
Perfect
  
Imperfect
  
Toughness
Not Available
  
2.1
  
Specific Gravity
2.250
  
2.75-2.92
  
Transparency
Opaque
  
Opaque
  
Density
2.2 g/cm3
  
1.5-2.5 g/cm3
  
Thermal Properties
  
  
Specific Heat Capacity
0.92 kJ/Kg K
  
10
0.88 kJ/Kg K
  
13
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant
  
Heat Resistant
  
Deposits in Eastern Continents
  
  
Asia
China, India, Kazakhstan, Mongolia, Russia, Uzbekistan
  
India, Russia
  
Africa
Namibia, Nigeria, South Africa
  
South Africa
  
Europe
Austria, Denmark, Germany, Great Britain, Netherlands, Poland, Sweden, Switzerland, United Kingdom
  
Iceland
  
Others
Greenland
  
Not Yet Found
  
Deposits in Western Continents
  
  
North America
Canada, USA
  
Canada, USA
  
South America
Brazil
  
Brazil
  
Deposits in Oceania Continent
  
  
Australia
New South Wales, New Zealand, Western Australia
  
Not Yet Found
  
All about Gritstone and Picrite Properties
Know all about Gritstone and Picrite properties here. All properties of rocks are important as they define the type of rock and its application. Gritstone belongs to Sedimentary Rocks while Picrite belongs to Igneous Rocks.Texture of Gritstone is Earthy whereas that of Picrite is Earthy, Rough. Gritstone appears Layered and Foliated and Picrite appears Rough and Shiny. The luster of Gritstone is dull while that of Picrite is subvitreous to dull. Gritstone and Picrite are available in beige, black, brown, colourless, cream, dark brown, green, grey, light green, light to dark grey, pink, red, white, yellow colors. The commercial uses of Gritstone are an oil and gas reservoir, as a feed additive for livestock, gemstone, metallurgical flux, production of lime, soil conditioner, source of magnesia (mgo), tombstones and that of Picrite are as a feed additive for livestock, as armour rock for sea walls, metallurgical flux, pottery, source of magnesia (mgo).