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Essexite  and Chert


Chert and Essexite 


Definition

Definition
Essexite which is also known as nepheline monzogabbro, is a dark gray or black holocrystalline plutonic Iigneous Rock   
Chert is a hard, dark, opaque sedimentary rock which is composed of silica with an amorphous fine-grained texture   

History
  
  

Origin
USA   
Unknown   

Discoverer
Unknown   
Unknown   

Etymology
From the locality in Essex County, Massachusetts,US   
From flint-like quartz, 1670s, of unknown origin- a local term, which has been taken into geological use   

Class
Igneous Rocks   
Sedimentary Rocks   

Sub-Class
Durable Rock, Hard Rock   
Durable Rock, Hard Rock   

Family
  
  

Group
Plutonic   
Not Applicable   

Other Categories
Fine Grained Rock, Opaque Rock   
Fine Grained Rock, Opaque Rock   

Texture

Texture
Granular   
Banded, Rough   

Color
Dark Grey to Black   
Black, Brown, Green, Grey, Red, White   

Maintenance
Less   
Less   

Durability
Durable   
Durable   

Water Resistant
Yes   
Yes   

Scratch Resistant
Yes   
Yes   

Stain Resistant
Yes   
Yes   

Wind Resistant
Yes   
No   

Acid Resistant
No   
Yes   

Appearance
Banded   
Glassy or Pearly   

Uses

Architecture
  
  

Interior Uses
Decorative Aggregates, Homes, Interior Decoration   
Decorative Aggregates, Homes   

Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone   
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings   

Other Architectural Uses
Curbing   
Curbing   

Industry
  
  

Construction Industry
As Dimension Stone, Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate   
Arrowheads, Construction Aggregate, Cutting Tool, Spear Points   

Medical Industry
Not Yet Used   
Not Yet Used   

Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines   
Artifacts, Monuments   

Other Uses
  
  

Commercial Uses
Cemetery Markers, Commemorative Tablets, Jewelry, Sea Defence, Tombstones   
Creating Artwork, Gemstone, In fire-starting tools, Jewelry, To ignite fire, Used in flintlock firearms   

Types

Types
Not Available   
Flint, Jasper, Radiolarite, Common Chert, Chalcedony, Agate, Onyx, Opal, Magadi-type Chert, Porcelanite, Siliceous Sinter   

Features
Is one of the oldest rock, Smooth to touch   
Clasts are smooth to touch, Easily splits into thin plates, Has High structural resistance against erosion and climate   

Archaeological Significance
  
  

Monuments
Used   
Used   

Famous Monuments
Data Not Available   
Data Not Available   

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   

Fossils
Absent   
Present   

Formation

Formation
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.   
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.   

Composition
  
  

Mineral Content
Augite, Feldspar, Hornblende, Nepheline, Olivine, Plagioclase, Pyroxene   
Quartz, Silicon   

Compound Content
Aluminium Oxide, Ba, Ca, Cs, Potassium, Rb, Sodium, Sr   
Silicon Dioxide   

Transformation
  
  

Metamorphism
Yes   
No   

Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism   
Not Applicable   

Weathering
Yes   
No   

Types of Weathering
Biological Weathering, Chemical Weathering   
Not Applicable   

Erosion
Yes   
Yes   

Types of Erosion
Coastal Erosion, Glacier Erosion, Water Erosion   
Chemical Erosion   

Properties

Physical Properties
  
  

Hardness
7   
6.5-7   

Grain Size
Fine Grained   
Very fine-grained   

Fracture
Conchoidal   
Uneven, Splintery or Conchoidal   

Streak
Black   
White   

Porosity
Highly Porous   
Highly Porous   

Luster
Not Available   
Waxy and Dull   

Compressive Strength
Not Available   
450.00 N/mm2   
1

Cleavage
Not Available   
Non-Existent   

Toughness
1.6   
1.5   

Specific Gravity
Not Available   
2.5-2.8   

Transparency
Opaque   
Translucent to Opaque   

Density
Not Available   
2.7 g/cm3   

Thermal Properties
  
  

Specific Heat Capacity
Not Available   
0.74 kJ/Kg K   
19

Resistance
Impact Resistant, Pressure Resistant, Wear Resistant   
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant   

Reserves

Deposits in Eastern Continents
  
  

Asia
India, Russia   
China, India, Iran, Japan, Oman, Russia, Saudi Arabia, Taiwan, Thailand, Vietnam   

Africa
South Africa   
Kenya, Morocco, South Africa, Tanzania   

Europe
Germany, Greece, Italy, Scotland, Turkey   
Austria, France, Greece, Italy, Malta, Poland, Portugal, Serbia, Spain, Sweden, United Kingdom   

Others
Greenland   
Greenland, Mid-Atlantic Ridge   

Deposits in Western Continents
  
  

North America
Canada, USA   
Canada, Mexico, USA   

South America
Brazil, Colombia, Venezuela   
Bolivia, Brazil   

Deposits in Oceania Continent
  
  

Australia
New Zealand, Queensland   
New South Wales, Queensland, South Australia, Western Australia   

Summary >>
<< Reserves

All about Essexite  and Chert Properties

Know all about Essexite  and Chert properties here. All properties of rocks are important as they define the type of rock and its application. Essexite  belongs to Igneous Rocks while Chert belongs to Sedimentary Rocks.Texture of Essexite  is Granular whereas that of Chert is Banded, Rough. Essexite  appears Banded and Chert appears Glassy or Pearly. The luster of Essexite  is not available while that of Chert is waxy and dull. Essexite  is available in dark grey to black colors whereas Chert is available in black, brown, green, grey, red, white colors. The commercial uses of Essexite  are cemetery markers, commemorative tablets, jewelry, sea defence, tombstones and that of Chert are creating artwork, gemstone, in fire-starting tools, jewelry, to ignite fire, used in flintlock firearms.

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