Definition
Nephelinite is a fine-grained or aphanitic igneous rock made up almost entirely of nepheline and clinopyroxene (variety augite).
Rhyolite is a fine-grained igneous rock which is rich in silica
Origin
Brazil
North America
Discoverer
Unknown
Ferdinand von Richthofen
Etymology
from French néphéline, from Greek nephelē
From German Rhyolit, from Greek rhuax lava stream + lithos stone
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock
Texture
Aphanitic
Aphanitic, Glassy, Porphyritic
Color
Black, Brown, Colourless, Green, Grey, White
Grey, White, Light Black
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Skeletal
Banded
Interior Uses
Decorative Aggregates, Homes, Interior Decoration
Decorative Aggregates, Homes, Hotels, Interior Decoration, Kitchens
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
As Building Stone, As Facing Stone, Paving Stone, Office Buildings
Other Architectural Uses
Curbing
Not Yet Used
Construction Industry
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate
Arrowheads, As Dimension Stone, Building houses or walls, Construction Aggregate, Cutting Tool, for Road Aggregate, Knives
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)
Gemstone, Laboratory bench tops, Jewelry
Types
Peralkaline Nephelinite
Pumice Rocks, Obsidian Rocks, Perlite Rocks, Porphyritic Rocks.
Features
Host Rock for Lead
Acidic in nature, Available in lots of colors
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
Not Used
Petroglyphs
Not Used
Not 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.
Rhyolite is a felsic extrusive rock and due to its high silica content, rhyolite lava is very viscous and is volcanic equivalent of granite.
Mineral Content
Clinopyroxene, Nepheline, Plagioclase
Biotite, Feldspar, Hornblade, Plagioclase, Pyroxene, Quartz
Compound Content
Ca, CaO, Carbon, Cl, MgO
Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide, Sodium
Types of Metamorphism
Contact Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Regional 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, Sea Erosion, Water Erosion, Wind Erosion
Grain Size
Fine Grained
Large and Coarse Grained
Fracture
Flat
Sub-conchoidal
Porosity
Less Porous
Highly Porous
Luster
Vitreous to Metallic
Earthy
Cleavage
Imperfect
Not Available
Specific Gravity
2.4-2.9
2.65-2.67
Transparency
Opaque
Opaque
Density
2.5-3 g/cm3
2.4-2.6 g/cm3
Specific Heat Capacity
Not Available
Resistance
Heat Resistant
Heat Resistant, Wear Resistant
Deposits in Eastern Continents
Africa
Rwanda, Tanzania
Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa
Europe
Not Yet Found
Germany, Iceland, Ireland, Italy, Spain
Others
Hawaii Islands
Not Yet Found
Deposits in Western Continents
North America
Canada, USA
Canada, USA
South America
Colombia
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Deposits in Oceania Continent
Australia
Not Yet Found
New Zealand, Queensland, Western Australia
All about Nephelinite and Rhyolite Properties
Know all about Nephelinite and Rhyolite properties here. All properties of rocks are important as they define the type of rock and its application. Nephelinite and Rhyolite belong to Igneous Rocks.Texture of Nephelinite is Aphanitic whereas that of Rhyolite is Aphanitic, Glassy, Porphyritic. Nephelinite appears Skeletal and Rhyolite appears Banded. The luster of Nephelinite is vitreous to metallic while that of Rhyolite is earthy. Nephelinite is available in black, brown, colourless, green, grey, white colors whereas Rhyolite is available in grey, white, light black colors. The commercial uses of Nephelinite are creating artwork, soil conditioner, source of magnesia (mgo) and that of Rhyolite are gemstone, laboratory bench tops, jewelry.