Definition
Picrite is a variety of high-magnesium olivine basalt that is very rich in the mineral olivine
Marl is an unconsolidated sedimentary rock consisting of clay and lime
Discoverer
Unknown
William Smith
Etymology
From Greek pikros bitter + -ite, 19th century
From Old French marle, from Late Latin marglia
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Soft Rock
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Earthy, Rough
Earthy
Color
Black, Brown, Green, Grey, Pink, White, Yellow
Beige, Brown, Green, Grey, White
Durability
Durable
Durable
Appearance
Rough and Shiny
Rough and Dull
Interior Uses
Countertops, Decorative Aggregates, Homes, Interior Decoration
Decorative Aggregates, Floor Tiles
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
As Building Stone, Roof Tiles
Other Architectural Uses
Curbing
Curbing
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.
Cement Manufacture, Construction Aggregate, for Road Aggregate, Making natural cement, Raw material for the manufacture of mortar
Antiquity Uses
Artifacts, Monuments, Sculpture
Artifacts, Jewellery, Sculpture, Small Figurines
Commercial Uses
As a Feed Additive for Livestock, As armour rock for sea walls, Metallurgical Flux, Pottery, Source of Magnesia (MgO)
Creating Artwork, Soil Conditioner
Types
Oceanite
Clay Marl ,Blue Marl, Red Marl, High Bank Marl, Shell Layer Marl, Under Shell Layer Marl, Sand Marl, Green Marl, Grey Marl and Clayey Marl
Features
Host Rock for Lead
Generally rough to touch, Is one of the oldest rock, Splintery, Very fine grained rock
Archaeological Significance
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.
Marl forms when very fine-grained clay particles are deposited in water which settles at the bottom of water bodies and are compacted by overlying sediment; the water squeezes out and hence forming Marl rock.
Mineral Content
Biotite, Olivine, Plagioclase, Pyrrhotite
Calcite, Clay, Dolomite, Gypsum, Micas, Pyrite, Quartz
Compound Content
Al, CaO, Carbon Dioxide, Mg, MgO
Aluminium Oxide, NaCl, CaO, Iron(III) Oxide, Silicon Dioxide
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Impact Metamorphism, Regional Metamorphism
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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, Wind Erosion
Grain Size
Fine Grained
Very fine-grained
Fracture
Uneven
Conchoidal
Streak
White, Greenish White or Grey
White
Porosity
Less Porous
Highly Porous
Luster
Subvitreous to Dull
Dull
Specific Gravity
2.75-2.92
2.2-2.8
Transparency
Opaque
Opaque
Density
1.5-2.5 g/cm3
2.4-2.8 g/cm3
Resistance
Heat Resistant
Heat Resistant, Impact Resistant
Deposits in Eastern Continents
Asia
India, Russia
India, Pakistan, Russia
Africa
South Africa
Ethiopia, Kenya, Morocco, South Africa
Europe
Iceland
Austria, France, Germany, Greece, Italy, Romania, Scotland, Spain, Switzerland
Deposits in Western Continents
North America
Canada, USA
USA
South America
Brazil
Colombia, Ecuador, Peru
Deposits in Oceania Continent
Australia
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New South Wales, Victoria, Western Australia
All about Picrite and Marl Properties
Know all about Picrite and Marl properties here. All properties of rocks are important as they define the type of rock and its application. Picrite belongs to Igneous Rocks while Marl belongs to Sedimentary Rocks.Texture of Picrite is Earthy, Rough whereas that of Marl is Earthy. Picrite appears Rough and Shiny and Marl appears Rough and Dull. The luster of Picrite is subvitreous to dull while that of Marl is dull. Picrite is available in black, brown, green, grey, pink, white, yellow colors whereas Marl is available in beige, brown, green, grey, white 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 Marl are creating artwork, soil conditioner.