Definition
Chert is a hard, dark, opaque sedimentary rock which is composed of silica with an amorphous fine-grained texture
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 flint-like quartz, 1670s, of unknown origin- a local term, which has been taken into geological use
From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius
Class
Sedimentary Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Group
Not Applicable
Volcanic
Other Categories
Fine Grained Rock, Opaque Rock
Opaque Rock
Texture
Banded, Rough
Glassy
Color
Black, Brown, Green, Grey, Red, White
Black, Blue, Brown, Green, Orange, Red, Tan, Yellow
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Glassy or Pearly
Shiny
Interior Uses
Decorative Aggregates, Homes
Decorative Aggregates, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings
Garden Decoration
Other Architectural Uses
Curbing
Not Yet Used
Construction Industry
Arrowheads, Construction Aggregate, Cutting Tool, Spear Points
Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points
Medical Industry
Not Yet Used
Surgery
Antiquity Uses
Artifacts, Monuments
Artifacts, Jewellery
Commercial Uses
Creating Artwork, Gemstone, In fire-starting tools, Jewelry, To ignite fire, Used in flintlock firearms
Creating Artwork, Mirror, Used in aquariums
Types
Flint, Jasper, Radiolarite, Common Chert, Chalcedony, Agate, Onyx, Opal, Magadi-type Chert, Porcelanite, Siliceous Sinter
Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian
Features
Clasts are smooth to touch, Easily splits into thin plates, Has High structural resistance against erosion and climate
Blocks negativity, Helps to protect against depression
Archaeological Significance
Monuments
Used
Not Yet Used
Famous Monuments
Data Not Available
Not Applicable
Sculpture
Not Yet Used
Not Yet Used
Famous Sculptures
Not Applicable
Not Applicable
Pictographs
Not Used
Used
Petroglyphs
Not Used
Used
Figurines
Not Yet Used
Not Yet Used
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.
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
Quartz, Silicon
Not Available
Compound Content
Silicon Dioxide
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Types of Metamorphism
Not Applicable
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
Types of Weathering
Not Applicable
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Grain Size
Very fine-grained
Not Applicable
Fracture
Uneven, Splintery or Conchoidal
Conchoidal
Porosity
Highly Porous
Very Less Porous
Luster
Waxy and Dull
Vitreous
Cleavage
Non-Existent
Non-Existent
Toughness
1.5
Not Available
Specific Gravity
2.5-2.8
2.6-2.7
Transparency
Translucent to Opaque
Translucent
Density
2.7 g/cm3
2.6 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
Afghanistan, Indonesia, Japan, Russia
Africa
Kenya, Morocco, South Africa, Tanzania
Kenya
Europe
Austria, France, Greece, Italy, Malta, Poland, Portugal, Serbia, Spain, Sweden, United Kingdom
Greece, Hungary, Iceland, Italy, Turkey
Others
Greenland, Mid-Atlantic Ridge
Not Yet Found
Deposits in Western Continents
North America
Canada, Mexico, USA
Canada, Mexico, USA
South America
Bolivia, Brazil
Argentina, Chile, Ecuador, Peru
Deposits in Oceania Continent
Australia
New South Wales, Queensland, South Australia, Western Australia
New Zealand
Chert 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. Chert vs Obsidian characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Chert and Properties of Obsidian. Learn more about Chert vs Obsidian in the next section. The interior uses of Chert include Decorative aggregates and Homes whereas the interior uses of Obsidian include Decorative aggregates and Interior decoration. Due to some exceptional properties of Chert and Obsidian, 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 Obsidian include Arrowheads, Cutting tool, Knives, Scrapers, Spear points.
More about Chert and Obsidian
Here you can know more about Chert and Obsidian. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Chert and Obsidian consists of mineral content and compound content. The mineral content of Chert includes Quartz, Silicon and mineral content of Obsidian is not available. You can also check out the list of all Sedimentary Rocks. When we have to compare Chert vs Obsidian, 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, Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors. Appearance of Chert is Glassy or Pearly and that of Obsidian is Shiny. Properties of rock is another aspect for Chert vs Obsidian. The hardness of Chert is 6.5-7 and that of Obsidian is 5-5.5. The types of Chert are Flint, Jasper, Radiolarite, Common Chert, Chalcedony, Agate, Onyx, Opal, Magadi-type Chert, Porcelanite, Siliceous Sinter 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 Chert and Obsidian is white. The specific heat capacity of Chert is 0.74 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.Chert is heat resistant, impact resistant, pressure resistant, wear resistant whereas Obsidian is heat resistant, impact resistant.
