Definition
Nephelinite is a fine-grained or aphanitic igneous rock made up almost entirely of nepheline and clinopyroxene (variety augite).
Obsidian is a naturally occurring volcanic glass formed as an extrusive igneous rock. It is produced when felsic lava extruded from a volcano cools rapidly with minimum crystal growth
Discoverer
Unknown
Obsius
Etymology
from French néphéline, from Greek nephelē
From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Other Categories
Fine Grained Rock, Opaque Rock
Opaque Rock
Color
Black, Brown, Colourless, Green, Grey, White
Black, Blue, Brown, Green, Orange, Red, Tan, Yellow
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Skeletal
Shiny
Interior Uses
Decorative Aggregates, Homes, Interior Decoration
Decorative Aggregates, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
Garden Decoration
Other Architectural Uses
Curbing
Not Yet Used
Construction Industry
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate
Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points
Medical Industry
Not Yet Used
Surgery
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
Artifacts, Jewellery
Commercial Uses
Creating Artwork, Soil Conditioner, Source of Magnesia (MgO)
Creating Artwork, Mirror, Used in aquariums
Types
Peralkaline Nephelinite
Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian
Features
Host Rock for Lead
Blocks negativity, Helps to protect against depression
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.
When the lava is released from volcano, it undergoes a very rapid cooling which freezes the mechanisms of crystallization. The result is a volcanic glass with a uniform smooth texture.
Mineral Content
Clinopyroxene, Nepheline, Plagioclase
Not Available
Compound Content
Ca, CaO, Carbon, Cl, MgO
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Types of Metamorphism
Contact Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact 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, Coastal Erosion, Glacier Erosion
Grain Size
Fine Grained
Not Applicable
Porosity
Less Porous
Very Less Porous
Luster
Vitreous to Metallic
Vitreous
Cleavage
Imperfect
Non-Existent
Toughness
2.7
Not Available
Specific Gravity
2.4-2.9
2.6-2.7
Transparency
Opaque
Translucent
Density
2.5-3 g/cm3
2.6 g/cm3
Resistance
Heat Resistant
Heat Resistant, Impact Resistant
Deposits in Eastern Continents
Asia
Japan
Afghanistan, Indonesia, Japan, Russia
Africa
Rwanda, Tanzania
Kenya
Europe
Not Yet Found
Greece, Hungary, Iceland, Italy, Turkey
Others
Hawaii Islands
Not Yet Found
Deposits in Western Continents
North America
Canada, USA
Canada, Mexico, USA
South America
Colombia
Argentina, Chile, Ecuador, Peru
Deposits in Oceania Continent
Australia
Not Yet Found
New Zealand
Nephelinite vs Obsidian Characteristics
Though some rocks look identical, they have certain characteristics which distinguish them from others. Characteristics of rocks include texture, appearance, color, fracture, streak, hardness etc. Nephelinite vs Obsidian characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Nephelinite and Properties of Obsidian. Learn more about Nephelinite vs Obsidian in the next section. The interior uses of Nephelinite include Decorative aggregates, Homes and Interior decoration whereas the interior uses of Obsidian include Decorative aggregates and Interior decoration. Due to some exceptional properties of Nephelinite and Obsidian, they have various applications in construction industry. The uses of Nephelinite in construction industry include As dimension stone, Cement manufacture, Construction aggregate, For road aggregate and that of Obsidian include Arrowheads, Cutting tool, Knives, Scrapers, Spear points.
More about Nephelinite and Obsidian
Here you can know more about Nephelinite and Obsidian. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Nephelinite and Obsidian consists of mineral content and compound content. The mineral content of Nephelinite includes Clinopyroxene, Nepheline, Plagioclase and mineral content of Obsidian is not available. You can also check out the list of all Igneous Rocks. When we have to compare Nephelinite vs Obsidian, the texture, color and appearance plays an important role in determining the type of rock. Nephelinite is available in black, brown, colourless, green, grey, white colors whereas, Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors. Appearance of Nephelinite is Skeletal and that of Obsidian is Shiny. Properties of rock is another aspect for Nephelinite vs Obsidian. The hardness of Nephelinite is 6.5 and that of Obsidian is 5-5.5. The types of Nephelinite are Peralkaline Nephelinite whereas types of Obsidian are Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Nephelinite and Obsidian is white. The specific heat capacity of Nephelinite is 0.88 kJ/Kg K and that of Obsidian is 0.92 kJ/Kg K. Depending on the properties like hardness, toughness, specific heat capacity, porosity etc., rocks are resistant to heat, wear, impact, etc.Nephelinite is heat resistant whereas Obsidian is heat resistant, impact resistant.