Definition
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
Oil Shale is a fine-grained sedimentary rock from which oil is extracted
Discoverer
Obsius
Unknown
Etymology
From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius
From Old English scealu in its base sense of thing that divides or separate
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Soft Rock
Group
Volcanic
Not Applicable
Other Categories
Opaque Rock
Fine Grained Rock, Opaque Rock
Color
Black, Blue, Brown, Green, Orange, Red, Tan, Yellow
Black, Brown, Buff, Green, Grey, Red, Yellow
Durability
Durable
Durable
Interior Uses
Decorative Aggregates, Interior Decoration
Not Yet Used
Exterior Uses
Garden Decoration
Not Yet Used
Other Architectural Uses
Not Yet Used
Not Yet Used
Construction Industry
Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points
Cement Manufacture, Construction Aggregate, for Road Aggregate, Serves as an Oil and Gas Reservoir rock
Medical Industry
Surgery
Not Yet Used
Antiquity Uses
Artifacts, Jewellery
Artifacts
Commercial Uses
Creating Artwork, Mirror, Used in aquariums
An Oil and Gas Reservoir
Types
Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian
Carbonate-rich Shale, Siliceous Shale and Cannel Shale
Features
Blocks negativity, Helps to protect against depression
Easily splits into thin plates, Generally rough to touch, Is one of the oldest rock, Very fine grained rock
Archaeological Significance
Monuments
Not Yet Used
Not Yet Used
Famous Monuments
Not Applicable
Not Applicable
Sculpture
Not Yet Used
Not Yet Used
Famous Sculptures
Not Applicable
Not Applicable
Pictographs
Used
Not Used
Petroglyphs
Used
Not Used
Figurines
Not Yet Used
Not Yet Used
Formation
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.
Oil Shale forms on the beds of seas and lakes and its formation starts with the organic debris settling and accumulating at the bottom of a lake or sea which are then transformed into rock with the help of high temperature and pressure.
Mineral Content
Not Available
Albite, Biotite, Calcite, Chert, Chlorite, Dolomite, Hematite, Micas, Muscovite or Illite, Pyrite, Quartz, Silica, Sulfides
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Ca, Fe, Mg, Silicon Dioxide, Sodium
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
Not Applicable
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Chemical Erosion, Sea Erosion, Water Erosion
Grain Size
Not Applicable
Very fine-grained
Fracture
Conchoidal
Not Available
Porosity
Very Less Porous
Highly Porous
Compressive Strength
Not Available
Cleavage
Non-Existent
Slaty
Toughness
Not Available
2.6
Specific Gravity
2.6-2.7
2.2-2.8
Transparency
Translucent
Opaque
Density
2.6 g/cm3
2.4-2.8 g/cm3
Resistance
Heat Resistant, Impact Resistant
Heat Resistant, Impact Resistant
Deposits in Eastern Continents
Asia
Afghanistan, Indonesia, Japan, Russia
Bangladesh, China, India, Israel, Jordan, Russia, Syria, Thailand, Turkey
Africa
Kenya
Ethiopia, Kenya, Morocco, South Africa, Tanzania
Europe
Greece, Hungary, Iceland, Italy, Turkey
Austria, France, Germany, Greece, Italy, Romania, Scotland, Spain, Sweden, Switzerland
Others
Not Yet Found
Greenland, Not Yet Found
Deposits in Western Continents
North America
Canada, Mexico, USA
Canada, USA
South America
Argentina, Chile, Ecuador, Peru
Bolivia, Brazil, Chile, Colombia, Ecuador, Peru, Venezuela
Deposits in Oceania Continent
Australia
New Zealand
New South Wales, New Zealand, Queensland, Victoria, Western Australia
All about Obsidian and Oil shale Properties
Know all about Obsidian and Oil shale properties here. All properties of rocks are important as they define the type of rock and its application. Obsidian belongs to Igneous Rocks while Oil shale belongs to Sedimentary Rocks.Texture of Obsidian is Glassy whereas that of Oil shale is Splintery. Obsidian appears Shiny and Oil shale appears Muddy. The luster of Obsidian is vitreous while that of Oil shale is dull. Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors whereas Oil shale is available in black, brown, buff, green, grey, red, yellow colors. The commercial uses of Obsidian are creating artwork, mirror, used in aquariums and that of Oil shale are an oil and gas reservoir.