Definition
Picrite is a variety of high-magnesium olivine basalt that is very rich in the mineral olivine
Chalk is a soft, white, powdery limestone consisting mainly of fossil shells of foraminifers
Origin
Hawaii Islands
Unknown
Discoverer
Unknown
Unknown
Etymology
From Greek pikros bitter + -ite, 19th century
From old English cealc chalk, lime, plaster; pebble, from Greek khalix small pebble, in English transferred to the opaque, white, soft limestone
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Soft Rock
Group
Volcanic
Not Applicable
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Earthy, Rough
Clastic or Non-Clastic
Color
Black, Brown, Colourless, Green, Grey, Pink, White, Yellow
Grey, White, Yellow
Durability
Durable
Durable
Appearance
Rough and Shiny
Soft
Interior Uses
Countertops, Decorative Aggregates, Homes, Interior Decoration
Decorative Aggregates, Homes, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration
Other Architectural Uses
Curbing
Powder
Construction Industry
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.
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate, Making natural cement, raw material for manufacture of quicklime and slaked lime, Source of calcium
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Monuments, Sculpture
Artifacts, Monuments, Sculpture, Small Figurines
Commercial Uses
As a Feed Additive for Livestock, As armour rock for sea walls, Metallurgical Flux, Pottery, Source of Magnesia (MgO)
Alumina Refineries, Creating Artwork, Drawing on blackboards, Gymnasts, athletes and mountain climbers use for grip, In aquifers, Paper Industry, Production of Lime, Raw material for manufacture of quicklime, slaked lime, Soil Conditioner, Whiting, Whiting material in toothpaste, paint and paper
Types
Oceanite
Not Available
Features
Host Rock for Lead
Clasts are smooth to touch, Is one of the oldest rock, Smooth to touch, Very fine grained rock
Archaeological Significance
Famous Monuments
Data Not Available
Data Not Available
Famous Sculptures
Data Not Available
Data Not Available
Pictographs
Not Used
Used
Petroglyphs
Not Used
Used
Formation
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.
Chalk is formed from lime mud, which accumulates on the sea floor which is then transformed into rock by geological processes.
Mineral Content
Biotite, Olivine, Plagioclase, Pyrrhotite
Calcite, Clay, Clay Minerals, Quartz, Sand
Compound Content
Al, CaO, Carbon Dioxide, Mg, MgO
Ca, NaCl, CaO
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Impact Metamorphism, Regional Metamorphism
Not Applicable
Types of Weathering
Biological Weathering
Biological Weathering, Chemical Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Chemical Erosion, Coastal Erosion, Water Erosion
Grain Size
Fine Grained
Very fine-grained
Fracture
Uneven
Not Available
Streak
White, Greenish White or Grey
White
Porosity
Less Porous
Highly Porous
Luster
Subvitreous to Dull
Dull
Compressive Strength
Not Available
Cleavage
Imperfect
Non-Existent
Specific Gravity
2.75-2.92
2.3-2.4
Transparency
Opaque
Opaque
Density
1.5-2.5 g/cm3
2.49-2.50 g/cm3
Resistance
Heat Resistant
Heat Resistant
Deposits in Eastern Continents
Asia
India, Russia
Brunei, India, Indonesia, Malaysia, Singapore, Thailand, Vietnam
Africa
South Africa
Cameroon, Chad, Ghana, Kenya, Malawi, Sudan, Tanzania, Togo, Zambia, Zimbabwe
Europe
Iceland
England, France, Germany, Spain, United Kingdom
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
Canada, USA
Canada, USA
South America
Brazil
Colombia
Deposits in Oceania Continent
Australia
Not Yet Found
Adelaide, New Zealand, Queensland, Tonga, Victoria, Yorke Peninsula
All about Picrite and Chalk Properties
Know all about Picrite and Chalk properties here. All properties of rocks are important as they define the type of rock and its application. Picrite belongs to Igneous Rocks while Chalk belongs to Sedimentary Rocks.Texture of Picrite is Earthy, Rough whereas that of Chalk is Clastic or Non-Clastic. Picrite appears Rough and Shiny and Chalk appears Soft. The luster of Picrite is subvitreous to dull while that of Chalk is dull. Picrite and Chalk are available in black, brown, colourless, green, grey, pink, white, yellow colors. The commercial uses of Picrite are as a feed additive for livestock, as armour rock for sea walls, metallurgical flux, pottery, source of magnesia (mgo) and that of Chalk are alumina refineries, creating artwork, drawing on blackboards, gymnasts, athletes and mountain climbers use for grip, in aquifers, paper industry, production of lime, raw material for manufacture of quicklime, slaked lime, soil conditioner, whiting, whiting material in toothpaste, paint and paper.