Definition
Nephelinite is a fine-grained or aphanitic igneous rock made up almost entirely of nepheline and clinopyroxene (variety augite).
Dacite is a volcanic igneous rock which is rintermediate in composition between andesite and rhyolite
Origin
Brazil
Romania and Moldova, Europe
Discoverer
Unknown
Unknown
Etymology
from French néphéline, from Greek nephelē
From Dacia, a province of the Roman Empire which lay between the Danube River and Carpathian Mountains where the rock was first described
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Soft Rock
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Aphanitic
Aphanitic to Porphyritic
Color
Black, Brown, Colourless, Green, Grey, White
Bluish - Grey, Brown, Grey, Light to Dark Grey
Durability
Durable
Durable
Appearance
Skeletal
Vesicular
Interior Uses
Decorative Aggregates, Homes, Interior Decoration
Decorative Aggregates, Entryways, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
As Building Stone, Paving Stone, Garden Decoration
Other Architectural Uses
Curbing
Curbing
Construction Industry
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate
As Dimension Stone, Construction Aggregate, for Road Aggregate, Landscaping
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
Artifacts
Commercial Uses
Creating Artwork, Soil Conditioner, Source of Magnesia (MgO)
Commemorative Tablets, Creating Artwork
Types
Peralkaline Nephelinite
Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite
Features
Host Rock for Lead
Host Rock for Lead, Is one of the oldest rock
Archaeological Significance
Monuments
Used
Not Yet Used
Famous Monuments
Data Not Available
Not Applicable
Sculpture
Used
Not Yet Used
Famous Sculptures
Data Not Available
Not Applicable
Pictographs
Not Used
Used
Petroglyphs
Not Used
Used
Figurines
Used
Not Yet Used
Formation
Nephelinite 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.
Dacitic magma is formed by the subduction of young oceanic crust under a thick felsic continental plate. Further, the Oceanic crust is hydrothermally altered as quartz and sodium are added.
Mineral Content
Clinopyroxene, Nepheline, Plagioclase
Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon
Compound Content
Ca, CaO, Carbon, Cl, MgO
Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide
Types of Metamorphism
Contact Metamorphism
Burial Metamorphism, Cataclastic Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion, Water Erosion, Wind Erosion
Chemical Erosion
Grain Size
Fine Grained
Medium to Fine Coarse Grained
Porosity
Less Porous
Less Porous
Luster
Vitreous to Metallic
Subvitreous to Dull
Compressive Strength
Not Available
Cleavage
Imperfect
Perfect
Toughness
2.7
Not Available
Specific Gravity
2.4-2.9
2.86-2.87
Transparency
Opaque
Translucent
Density
2.5-3 g/cm3
2.77-2.771 g/cm3
Resistance
Heat Resistant
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Africa
Rwanda, Tanzania
Not Yet Found
Europe
Not Yet Found
France, Greece, Romania, Scotland, Spain
Others
Hawaii Islands
Not Yet Found
Deposits in Western Continents
North America
Canada, USA
USA
South America
Colombia
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Deposits in Oceania Continent
Australia
Not Yet Found
New Zealand, South Australia, Western Australia
All about Nephelinite and Dacite Properties
Know all about Nephelinite and Dacite properties here. All properties of rocks are important as they define the type of rock and its application. Nephelinite and Dacite belong to Igneous Rocks.Texture of Nephelinite is Aphanitic whereas that of Dacite is Aphanitic to Porphyritic. Nephelinite appears Skeletal and Dacite appears Vesicular. The luster of Nephelinite is vitreous to metallic while that of Dacite is subvitreous to dull. Nephelinite is available in black, brown, colourless, green, grey, white colors whereas Dacite is available in bluish - grey, brown, grey, light to dark grey colors. The commercial uses of Nephelinite are creating artwork, soil conditioner, source of magnesia (mgo) and that of Dacite are commemorative tablets, creating artwork.