Definition
Adakite is an intermediate to felsic volcanic rock that has geochemical characteristics of magma which is said to be formed by partial melting of altered basalt that is subducted below volcanic arcs
Nephelinite is a fine-grained or aphanitic igneous rock made up almost entirely of nepheline and clinopyroxene (variety augite).
Origin
Adak, Aleutian Islands
Brazil
Discoverer
Defant and Drummond
Unknown
Etymology
From Adak, Aleutian Islands
from French néphéline, from Greek nephelē
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Other Categories
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Porphyritic
Aphanitic
Color
Black, Brown, Light to Dark Grey
Black, Brown, Green, Grey, White
Durability
Durable
Durable
Appearance
Dull and Soft
Skeletal
Interior Uses
Decorative Aggregates, Floor Tiles, Homes, Hotels, Kitchens
Decorative Aggregates, Homes, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Office Buildings
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
Other Architectural Uses
Whetstones
Curbing
Construction Industry
As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate
Antiquity Uses
Monuments, Sculpture, Small Figurines
Artifacts, Monuments, Sculpture, Small Figurines
Commercial Uses
Commemorative Tablets, Pottery, Used in aquariums
Creating Artwork, Soil Conditioner, Source of Magnesia (MgO)
Types
Intermediate volcanic rock
Peralkaline Nephelinite
Features
Has High structural resistance against erosion and climate, Host rock for Diamond, Very fine grained rock
Host Rock for Lead
Archaeological Significance
Formation
Adakite rocks are formed when the hydrous fluids are released from minerals that break down in metamorphosed basalt, and rise into the mantle they initiate partial melting.
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.
Mineral Content
Olivine, Plagioclase, Pyroxene
Clinopyroxene, Nepheline, Plagioclase
Compound Content
Aluminium Oxide, MgO, Silicon Dioxide
Ca, CaO, Carbon, Cl, MgO
Types of Metamorphism
Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism
Contact Metamorphism
Types of Weathering
Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Coastal Erosion, Sea Erosion, Water Erosion
Chemical Erosion, Water Erosion, Wind Erosion
Grain Size
Fine to Medium Grained
Fine Grained
Streak
Bluish Black
White
Porosity
Less Porous
Less Porous
Luster
Grainy, Pearly and Vitreous
Vitreous to Metallic
Specific Gravity
-9999
2.4-2.9
Transparency
Opaque
Opaque
Density
-9999 g/cm3
2.5-3 g/cm3
Resistance
Heat Resistant, Pressure Resistant, Wear Resistant
Heat Resistant
Deposits in Eastern Continents
Africa
Ethiopia, Somalia, South Africa
Rwanda, Tanzania
Deposits in Western Continents
North America
Canada, USA
Canada, USA
South America
Brazil
Colombia
Deposits in Oceania Continent
All about Adakite and Nephelinite Properties
Know all about Adakite and Nephelinite properties here. All properties of rocks are important as they define the type of rock and its application. Adakite and Nephelinite belong to Igneous Rocks.Texture of Adakite is Porphyritic whereas that of Nephelinite is Aphanitic. Adakite appears Dull and Soft and Nephelinite appears Skeletal. The luster of Adakite is grainy, pearly and vitreous while that of Nephelinite is vitreous to metallic. Adakite is available in black, brown, light to dark grey colors whereas Nephelinite is available in black, brown, green, grey, white colors. The commercial uses of Adakite are commemorative tablets, pottery, used in aquariums and that of Nephelinite are creating artwork, soil conditioner, source of magnesia (mgo).