Definition
Chert is a hard, dark, opaque sedimentary rock which is composed of silica with an amorphous fine-grained texture
Comendite is a hard, peralkaline igneous rock, a type of light blue grey rhyolite
Discoverer
Unknown
Unknown
Etymology
From flint-like quartz, 1670s, of unknown origin- a local term, which has been taken into geological use
Comendite derives its name from the area of Le Commende on San Pietro Island in Italy
Class
Sedimentary Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
Other Categories
Fine Grained Rock, Opaque Rock
Medium Grained Rock, Opaque Rock
Texture
Banded, Rough
Porphyritic
Color
Black, Brown, Green, Grey, Red, White
Blue, Bluish - Grey
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Glassy or Pearly
Foliated
Interior Uses
Decorative Aggregates, Homes
Countertops, Decorative Aggregates, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings
As Building Stone, As Facing Stone, Garden Decoration
Other Architectural Uses
Curbing
Curbing
Construction Industry
Arrowheads, Construction Aggregate, Cutting Tool, Spear Points
Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate, Landscaping, Making natural cement, Raw material for the manufacture of mortar
Antiquity Uses
Artifacts, Monuments
Artifacts
Commercial Uses
Creating Artwork, Gemstone, In fire-starting tools, Jewelry, To ignite fire, Used in flintlock firearms
Cemetery Markers
Types
Flint, Jasper, Radiolarite, Common Chert, Chalcedony, Agate, Onyx, Opal, Magadi-type Chert, Porcelanite, Siliceous Sinter
Rhyolite
Features
Clasts are smooth to touch, Easily splits into thin plates, Has High structural resistance against erosion and climate
Very fine grained rock, It is One of the Oldest, Strongest and Hardest Rock
Archaeological Significance
Formation
Chert forms when microcrystals of silicon dioxide grow within soft sediments that become limestone or chalk. The chert formation can be either of chemical or biological origin.
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.
Mineral Content
Quartz, Silicon
Albite, Amphibole, Quartz
Compound Content
Silicon Dioxide
Al, Fe, Potassium Oxide
Types of Metamorphism
-
Cataclastic Metamorphism, Regional Metamorphism
Types of Weathering
-
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion
Coastal Erosion, Water Erosion
Grain Size
Very fine-grained
Medium Grained
Fracture
Uneven, Splintery or Conchoidal
Pervasive
Streak
White
Bluish Black
Porosity
Highly Porous
Highly Porous
Luster
Waxy and Dull
Dull
Specific Gravity
2.5-2.8
2.38
Transparency
Translucent to Opaque
Opaque
Density
2.7 g/cm3
-9999 g/cm3
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Impact Resistant
Deposits in Eastern Continents
Asia
China, India, Iran, Japan, Oman, Russia, Saudi Arabia, Taiwan, Thailand, Vietnam
China
Africa
Kenya, Morocco, South Africa, Tanzania
East Africa
Europe
Austria, France, Greece, Italy, Malta, Poland, Portugal, Serbia, Spain, Sweden, United Kingdom
Italy
Others
Greenland, Mid-Atlantic Ridge
-
Deposits in Western Continents
North America
Canada, Mexico, USA
-
South America
Bolivia, Brazil
-
Deposits in Oceania Continent
Australia
New South Wales, Queensland, South Australia, Western Australia
Queensland
Chert vs Comendite 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. Chert vs Comendite characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Chert and Properties of Comendite. Learn more about Chert vs Comendite in the next section. The interior uses of Chert include Decorative aggregates and Homes whereas the interior uses of Comendite include Countertops, Decorative aggregates and Interior decoration. Due to some exceptional properties of Chert and Comendite, they have various applications in construction industry. The uses of Chert in construction industry include Arrowheads, Construction aggregate, Cutting tool, Spear points and that of Comendite include Building houses or walls, Cement manufacture, Construction aggregate, For road aggregate, Landscaping, Making natural cement, Raw material for the manufacture of mortar.
More about Chert and Comendite
Here you can know more about Chert and Comendite. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Chert and Comendite consists of mineral content and compound content. The mineral content of Chert includes Quartz, Silicon and mineral content of Comendite includes Albite, Amphibole, Quartz. You can also check out the list of all Sedimentary Rocks. When we have to compare Chert vs Comendite, the texture, color and appearance plays an important role in determining the type of rock. Chert is available in black, brown, green, grey, red, white colors whereas, Comendite is available in blue, bluish - grey colors. Appearance of Chert is Glassy or Pearly and that of Comendite is Foliated. Properties of rock is another aspect for Chert vs Comendite. The hardness of Chert is 6.5-7 and that of Comendite is 6-7. The types of Chert are Flint, Jasper, Radiolarite, Common Chert, Chalcedony, Agate, Onyx, Opal, Magadi-type Chert, Porcelanite, Siliceous Sinter whereas types of Comendite are Rhyolite. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Chert is white while that of Comendite is bluish black. The specific heat capacity of Chert is 0.74 kJ/Kg K and that of Comendite 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.Chert is heat resistant, impact resistant, pressure resistant, wear resistant whereas Comendite is heat resistant, impact resistant.