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
-
Marl vs Picrite Characteristics
Though some rocks look identical, they have certain characteristics which distinguish them from others. Characteristics of rocks include texture, appearance, color, fracture, streak, hardness etc. Marl vs Picrite characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Marl and Properties of Picrite. Learn more about Marl vs Picrite in the next section. The interior uses of Marl include Decorative aggregates and Floor tiles whereas the interior uses of Picrite include Countertops, Decorative aggregates, Homes and Interior decoration. Due to some exceptional properties of Marl and Picrite, they have various applications in construction industry. The uses of Marl in construction industry include Cement manufacture, Construction aggregate, For road aggregate, Making natural cement, Raw material for the manufacture of mortar and that of Picrite include 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..
More about Marl and Picrite
Here you can know more about Marl and Picrite. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Marl and Picrite consists of mineral content and compound content. The mineral content of Marl includes Calcite, Clay, Dolomite, Gypsum, Micas, Pyrite, Quartz and mineral content of Picrite includes Biotite, Olivine, Plagioclase, Pyrrhotite. You can also check out the list of all Sedimentary Rocks. When we have to compare Marl vs Picrite, the texture, color and appearance plays an important role in determining the type of rock. Marl is available in beige, brown, green, grey, white colors whereas, Picrite is available in black, brown, green, grey, pink, white, yellow colors. Appearance of Marl is Rough and Dull and that of Picrite is Rough and Shiny. Properties of rock is another aspect for Marl vs Picrite. The hardness of Marl is 2-3 and that of Picrite is 6.8. The types of Marl are 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 whereas types of Picrite are Oceanite. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Marl is white while that of Picrite is white, greenish white or grey. The specific heat capacity of Marl is 0.80 kJ/Kg K and that of Picrite is 0.88 kJ/Kg K. Depending on the properties like hardness, toughness, specific heat capacity, porosity etc., rocks are resistant to heat, wear, impact, etc.Marl is heat resistant, impact resistant whereas Picrite is heat resistant.