Definition
Nephelinite is a fine-grained or aphanitic igneous rock made up almost entirely of nepheline and clinopyroxene (variety augite).
Gossan is intensely oxidized, weathered or decomposed rock, usually the upper and exposed part of an ore deposit or mineral vein.
Discoverer
Unknown
Cornish Gossen
Etymology
from French néphéline, from Greek nephelē
From Cornish gossen from gos, blood from Old Cornish guit
Class
Igneous Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Aphanitic
Rough, Sandy
Color
Black, Brown, Green, Grey, White
Brown, Brown- Black, Gold, Green, Rust
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Skeletal
Dull and Banded
Interior Uses
Decorative Aggregates, Homes, Interior Decoration
Countertops, Decorative Aggregates, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration, Office Buildings
Other Architectural Uses
Curbing
Curbing
Construction Industry
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
Artifacts
Commercial Uses
Creating Artwork, Soil Conditioner, Source of Magnesia (MgO)
Cemetery Markers, Commemorative Tablets, Gemstone
Types
Peralkaline Nephelinite
Translocated gossan and Leakage gossan
Features
Host Rock for Lead
Clasts are smooth to touch, Easily splits into thin plates
Archaeological Significance
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.
Earth movements can cause rocks to be either deeply buried or squeezed and hence the rocks are heated and put under great pressure.
Mineral Content
Clinopyroxene, Nepheline, Plagioclase
Apatite, Augite, Biotite, Bronzite, Calcite, Chert, Epidote, Feldspar, Hornblende, Micas, Plagioclase, Pyroxene, Quartz, Sulfides, Zircon
Compound Content
Ca, CaO, Carbon, Cl, MgO
Aluminium Oxide, CaO, Fe, FeO, Silicon Dioxide, Sulphur
Types of Metamorphism
Contact Metamorphism
-
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
-
Types of Erosion
Chemical Erosion, Water Erosion, Wind Erosion
Chemical Erosion, Sea Erosion, Wind Erosion
Grain Size
Fine Grained
Fine to Medium Grained
Streak
White
White to Grey
Porosity
Less Porous
Highly Porous
Luster
Vitreous to Metallic
Metallic
Specific Gravity
2.4-2.9
2.0
Transparency
Opaque
Opaque
Density
2.5-3 g/cm3
-9999 g/cm3
Resistance
Heat Resistant
Heat Resistant, Impact Resistant, Pressure Resistant
Deposits in Eastern Continents
Asia
Japan
China, India, Indonesia, Russia, Singapore, South Korea
Africa
Rwanda, Tanzania
Cape Verde, Ethiopia, Ghana, South Africa, Western Africa
Europe
-
Albania, France, Germany, Great Britain, United Kingdom
Deposits in Western Continents
North America
Canada, USA
Canada, USA
South America
Colombia
Brazil, Colombia, Ecuador
Deposits in Oceania Continent
Australia
-
New South Wales, South Australia, Western Australia
All about Nephelinite and Gossan Properties
Know all about Nephelinite and Gossan properties here. All properties of rocks are important as they define the type of rock and its application. Nephelinite belongs to Igneous Rocks while Gossan belongs to Metamorphic Rocks.Texture of Nephelinite is Aphanitic whereas that of Gossan is Rough, Sandy. Nephelinite appears Skeletal and Gossan appears Dull and Banded. The luster of Nephelinite is vitreous to metallic while that of Gossan is metallic. Nephelinite is available in black, brown, green, grey, white colors whereas Gossan is available in brown, brown- black, gold, green, rust colors. The commercial uses of Nephelinite are creating artwork, soil conditioner, source of magnesia (mgo) and that of Gossan are cemetery markers, commemorative tablets, gemstone.