Definition
Picrite is a variety of high-magnesium olivine basalt that is very rich in the mineral olivine
Nepheline Syenite is a holocrystalline plutonic rock resembling syenite but containing nepheline and lacking quartz
Origin
Hawaii Islands
Unknown
Discoverer
Unknown
Unknown
Etymology
From Greek pikros bitter + -ite, 19th century
From origin of a Palaeozoic nepheline syenite from northern Shanxi Province, China
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Earthy, Rough
Granular
Color
Black, Brown, Colourless, Green, Grey, Pink, White, Yellow
Brown, Buff, Cream, Green, Grey, Pink, White
Durability
Durable
Durable
Appearance
Rough and Shiny
Banded and Foilated
Interior Uses
Countertops, Decorative Aggregates, Homes, Interior Decoration
Countertops, Decorative Aggregates, Flooring, Homes, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
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.
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate, Landscaping, Making natural cement, Manufacture of Magnesium and Dolomite Refractories, Production of Glass and Ceramics
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Monuments, Sculpture
Artifacts, Monuments, Sculpture
Commercial Uses
As a Feed Additive for Livestock, As armour rock for sea walls, Metallurgical Flux, Pottery, Source of Magnesia (MgO)
Cemetery Markers, Creating Artwork
Types
Oceanite
Borolanite and Litchfieldite
Features
Host Rock for Lead
Application of acids on the surface causes cloudy frosting, Available in Lots of Colors and Patterns, Dissolves in hydrochloric acid, Is one of the oldest 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.
Nepheline Syenites are formed due to alkaline igneous activities and are generally formed in thick continental crustal areas or in Cordilleran subduction zones.
Mineral Content
Biotite, Olivine, Plagioclase, Pyrrhotite
Albite, Amphibole, Biotite, Cancrinite, Feldspar, Hornblende, Plagioclase, Pyroxene, Sodalite
Compound Content
Al, CaO, Carbon Dioxide, Mg, MgO
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Impact Metamorphism, Regional Metamorphism
Burial Metamorphism, Impact Metamorphism
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
Grain Size
Fine Grained
Fine Grained
Fracture
Uneven
Conchoidal to Uneven
Streak
White, Greenish White or Grey
White
Porosity
Less Porous
Less Porous
Luster
Subvitreous to Dull
Greasy to Dull
Toughness
2.1
Not Available
Specific Gravity
2.75-2.92
2.6
Transparency
Opaque
Translucent to Opaque
Density
1.5-2.5 g/cm3
2.6 g/cm3
Specific Heat Capacity
Not Available
Resistance
Heat Resistant
Heat Resistant, Impact Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
India, Russia
Indonesia, Iran, Russia, Saudi Arabia, Sri Lanka, Taiwan, Thailand, Turkey, Turkmenistan, Vietnam
Africa
South Africa
Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa
Europe
Iceland
Andorra, Finland, France, Great Britain, Italy, Norway, Portugal, Spain, Sweden
Others
Not Yet Found
Greenland
Deposits in Western Continents
North America
Canada, USA
Canada, USA
South America
Brazil
Brazil, Chile, Colombia, Uruguay, Venezuela
Deposits in Oceania Continent
Australia
Not Yet Found
New Zealand, Queensland, South Australia, Tasmania, Western Australia
All about Picrite and Nepheline Syenite Properties
Know all about Picrite and Nepheline Syenite properties here. All properties of rocks are important as they define the type of rock and its application. Picrite and Nepheline Syenite belong to Igneous Rocks.Texture of Picrite is Earthy, Rough whereas that of Nepheline Syenite is Granular. Picrite appears Rough and Shiny and Nepheline Syenite appears Banded and Foilated. The luster of Picrite is subvitreous to dull while that of Nepheline Syenite is greasy to dull. Picrite is available in black, brown, colourless, green, grey, pink, white, yellow colors whereas Nepheline Syenite is available in brown, buff, cream, green, grey, pink, 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 Nepheline Syenite are cemetery markers, creating artwork.