Definition
Nepheline Syenite is a holocrystalline plutonic rock resembling syenite but containing nepheline and lacking quartz
Comendite is a hard, peralkaline igneous rock, a type of light blue grey rhyolite
History
Origin
-
Italy
Discoverer
Unknown
Unknown
Etymology
From origin of a Palaeozoic nepheline syenite from northern Shanxi Province, China
Comendite derives its name from the area of Le Commende on San Pietro Island in Italy
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Family
Group
Plutonic
Volcanic
Other Categories
Fine Grained Rock, Opaque Rock
Medium Grained Rock, Opaque Rock
Texture
Granular
Porphyritic
Color
Brown, Buff, Cream, Green, Grey, Pink, White
Blue, Bluish - Grey
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Banded and Foilated
Foliated
Architecture
Interior Uses
Countertops, Decorative Aggregates, Flooring, Homes, Interior Decoration
Countertops, Decorative Aggregates, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
As Building Stone, As Facing Stone, Garden Decoration
Other Architectural Uses
Curbing
Curbing
Industry
Construction Industry
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate, Landscaping, Making natural cement, Manufacture of Magnesium and Dolomite Refractories, Production of Glass and Ceramics
Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate, Landscaping, Making natural cement, Raw material for the manufacture of mortar
Medical Industry
-
-
Antiquity Uses
Artifacts, Monuments, Sculpture
Artifacts
Other Uses
Commercial Uses
Cemetery Markers, Creating Artwork
Cemetery Markers
Types
Borolanite and Litchfieldite
Rhyolite
Features
Application of acids on the surface causes cloudy frosting, Available in Lots of Colors and Patterns, Dissolves in hydrochloric acid, Is one of the oldest rock
Very fine grained rock, It is One of the Oldest, Strongest and Hardest Rock
Archaeological Significance
Monuments
-
-
Famous Monuments
-
-
Sculpture
-
-
Famous Sculptures
-
-
Pictographs
-
-
Petroglyphs
-
-
Figurines
-
-
Fossils
Absent
Absent
Formation
Nepheline Syenites are formed due to alkaline igneous activities and are generally formed in thick continental crustal areas or in Cordilleran subduction zones.
Comendite is a type of Igneous rock which is formed due to cooling and solidification of lava or magma. It may form with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.
Composition
Mineral Content
Albite, Amphibole, Biotite, Cancrinite, Feldspar, Hornblende, Plagioclase, Pyroxene, Sodalite
Albite, Amphibole, Quartz
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Al, Fe, Potassium Oxide
Transformation
Metamorphism
✔
✘
✔
✘
Types of Metamorphism
Burial Metamorphism, Impact Metamorphism
Cataclastic Metamorphism, Regional Metamorphism
Weathering
✔
✘
✔
✘
Types of Weathering
Biological Weathering, Chemical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Erosion
✔
✘
✔
✘
Types of Erosion
Chemical Erosion
Coastal Erosion, Water Erosion
Physical Properties
Hardness
5.5-66-7
1
7
👆🏻
Grain Size
Fine Grained
Medium Grained
Fracture
Conchoidal to Uneven
Pervasive
Streak
White
Bluish Black
Porosity
Less Porous
Highly Porous
Luster
Greasy to Dull
Dull
Compressive Strength
150.00 N/mm292.40 N/mm2
0.15
450
👆🏻
Cleavage
-
-
Toughness
-
2
Specific Gravity
2.62.38
0
8.4
👆🏻
Transparency
Translucent to Opaque
Opaque
Density
2.6 g/cm3-9999 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
0.71 kJ/Kg K0.79 kJ/Kg K
0.14
3.2
👆🏻
Resistance
Heat Resistant, Impact Resistant, Wear Resistant
Heat Resistant, Impact Resistant
Deposits in Eastern Continents
Asia
Indonesia, Iran, Russia, Saudi Arabia, Sri Lanka, Taiwan, Thailand, Turkey, Turkmenistan, Vietnam
China
Africa
Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa
East Africa
Europe
Andorra, Finland, France, Great Britain, Italy, Norway, Portugal, Spain, Sweden
Italy
Others
Greenland
-
Deposits in Western Continents
North America
Canada, USA
-
South America
Brazil, Chile, Colombia, Uruguay, Venezuela
-
Deposits in Oceania Continent
Australia
New Zealand, Queensland, South Australia, Tasmania, Western Australia
Queensland