Definition
Comendite is a hard, peralkaline igneous rock, a type of light blue grey rhyolite
Essexite which is also known as nepheline monzogabbro, is a dark gray or black holocrystalline plutonic Iigneous Rock
Discoverer
Unknown
Unknown
Etymology
Comendite derives its name from the area of Le Commende on San Pietro Island in Italy
From the locality in Essex County, Massachusetts,US
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
Other Categories
Medium Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Porphyritic
Granular
Color
Blue, Bluish - Grey
Dark Grey to Black
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Foliated
Banded
Interior Uses
Countertops, Decorative Aggregates, Interior Decoration
Decorative Aggregates, Homes, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
Other Architectural Uses
Curbing
Curbing
Construction Industry
Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate, Landscaping, Making natural cement, Raw material for the manufacture of mortar
As Dimension Stone, Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate
Antiquity Uses
Artifacts
Artifacts, Monuments, Sculpture, Small Figurines
Commercial Uses
Cemetery Markers
Cemetery Markers, Commemorative Tablets, Jewelry, Sea Defence, Tombstones
Types
Rhyolite
Intermediate volcanic rock
Features
Very fine grained rock, It is One of the Oldest, Strongest and Hardest Rock
Is one of the oldest rock, Smooth to touch
Archaeological Significance
Formation
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.
Essexite is a type of igneous rock, which is usually dark grey to black plutonic rock. For the formation of essexite, suitable magma with exact composition of K, Ba, Rb, Cs, Sr should be produced.
Mineral Content
Albite, Amphibole, Quartz
Augite, Feldspar, Hornblende, Nepheline, Olivine, Plagioclase, Pyroxene
Compound Content
Al, Fe, Potassium Oxide
Aluminium Oxide, Ba, Ca, Cs, Potassium, Rb, Sodium, Sr
Types of Metamorphism
Cataclastic Metamorphism, Regional Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering
Types of Erosion
Coastal Erosion, Water Erosion
Coastal Erosion, Glacier Erosion, Water Erosion
Grain Size
Medium Grained
Fine Grained
Fracture
Pervasive
Conchoidal
Streak
Bluish Black
Black
Porosity
Highly Porous
Highly Porous
Specific Gravity
2.38
-9999
Transparency
Opaque
Opaque
Density
-9999 g/cm3
-9999 g/cm3
Resistance
Heat Resistant, Impact Resistant
Impact Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Africa
East Africa
South Africa
Europe
Italy
Germany, Greece, Italy, Scotland, Turkey
Deposits in Western Continents
North America
-
Canada, USA
South America
-
Brazil, Colombia, Venezuela
Deposits in Oceania Continent
Australia
Queensland
New Zealand, Queensland
Comendite vs Essexite 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. Comendite vs Essexite characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Comendite and Properties of Essexite . Learn more about Comendite vs Essexite in the next section. The interior uses of Comendite include Countertops, Decorative aggregates and Interior decoration whereas the interior uses of Essexite include Decorative aggregates, Homes and Interior decoration. Due to some exceptional properties of Comendite and Essexite , they have various applications in construction industry. The uses of Comendite in construction industry include Building houses or walls, Cement manufacture, Construction aggregate, For road aggregate, Landscaping, Making natural cement, Raw material for the manufacture of mortar and that of Essexite include As dimension stone, Building houses or walls, Cement manufacture, Construction aggregate, For road aggregate.
More about Comendite and Essexite
Here you can know more about Comendite and Essexite . The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Comendite and Essexite consists of mineral content and compound content. The mineral content of Comendite includes Albite, Amphibole, Quartz and mineral content of Essexite includes Augite, Feldspar, Hornblende, Nepheline, Olivine, Plagioclase, Pyroxene. You can also check out the list of all Igneous Rocks. When we have to compare Comendite vs Essexite , the texture, color and appearance plays an important role in determining the type of rock. Comendite is available in blue, bluish - grey colors whereas, Essexite is available in dark grey to black colors. Appearance of Comendite is Foliated and that of Essexite is Banded. Properties of rock is another aspect for Comendite vs Essexite . The hardness of Comendite is 6-7 and that of Essexite is 7. The types of Comendite are Rhyolite whereas types of Essexite are Intermediate volcanic rock. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Comendite is bluish black while that of Essexite is black. The specific heat capacity of Comendite is 0.79 kJ/Kg K and that of Essexite is 0.79 kJ/Kg K. Depending on the properties like hardness, toughness, specific heat capacity, porosity etc., rocks are resistant to heat, wear, impact, etc.Comendite is heat resistant, impact resistant whereas Essexite is impact resistant, pressure resistant, wear resistant.