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