Definition
Shale is a fine-grained sedimentary rock which is formed by the compaction of silt and clay-size mineral particles
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 German Schalstein laminated limestone, and Schalgebirge layer of stone in stratified rock. From Old English scealu in its base sense of- thing that divides or separate,
From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius
Class
Sedimentary Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Medium Hardness Rock
Group
Not Applicable
Volcanic
Other Categories
Fine Grained Rock, Opaque Rock
Opaque Rock
Texture
Clastic, Splintery
Glassy
Color
Black, Brown, Buff, Green, Grey, Red, Yellow
Black, Blue, Brown, Green, Orange, Red, Tan, Yellow
Durability
Durable
Durable
Interior Uses
Decorative Aggregates, Homes, Interior Decoration
Decorative Aggregates, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Office Buildings
Garden Decoration
Other Architectural Uses
Curbing
Not Yet Used
Construction Industry
Cement Manufacture, Construction Aggregate, for Road Aggregate, Making natural cement, Raw material for the manufacture of mortar
Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points
Medical Industry
Not Yet Used
Surgery
Antiquity Uses
Artifacts, Sculpture
Artifacts, Jewellery
Commercial Uses
Creating Artwork, Pottery
Creating Artwork, Mirror, Used in aquariums
Types
Red Shale, Black Shale, Green Shale, Grey Shale and Yellow Shale
Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian
Features
Easily splits into thin plates, Generally rough to touch, Very fine grained rock
Blocks negativity, Helps to protect against depression
Archaeological Significance
Monuments
Used
Not Yet Used
Famous Monuments
Jantar Mantar in India
Not Applicable
Sculpture
Used
Not Yet Used
Famous Sculptures
Data Not Available
Not Applicable
Figurines
Used
Not Yet Used
Formation
Shale forms when very fine-grained clay particles are deposited in water which settle at the bottom of water bodies. They are later compacted hence forming shale.
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
Albite, Biotite, Calcite, Chert, Chlorite, Dolomite, Hematite, Micas, Muscovite or Illite, Pyrite, Quartz, Silica, Sulfides
Not Available
Compound Content
Ca, Fe, Mg, Silicon Dioxide, Sodium
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
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Grain Size
Very fine-grained
Not Applicable
Fracture
Not Available
Conchoidal
Porosity
Highly Porous
Very Less Porous
Cleavage
Slaty
Non-Existent
Toughness
2.6
Not Available
Specific Gravity
2.2-2.8
2.6-2.7
Transparency
Opaque
Translucent
Density
2.4-2.8 g/cm3
2.6 g/cm3
Resistance
Heat Resistant, Impact Resistant
Heat Resistant, Impact Resistant
Deposits in Eastern Continents
Asia
Bangladesh, China, India, Russia
Afghanistan, Indonesia, Japan, Russia
Africa
Ethiopia, Kenya, Morocco, South Africa, Tanzania
Kenya
Europe
Austria, France, Germany, Greece, Italy, Romania, Scotland, Spain, Switzerland
Greece, Hungary, Iceland, Italy, Turkey
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
USA
Canada, Mexico, USA
South America
Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Argentina, Chile, Ecuador, Peru
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Queensland, Victoria, Western Australia
New Zealand
All about Shale and Obsidian Properties
Know all about Shale and Obsidian properties here. All properties of rocks are important as they define the type of rock and its application. Shale belongs to Sedimentary Rocks while Obsidian belongs to Igneous Rocks.Texture of Shale is Clastic, Splintery whereas that of Obsidian is Glassy. Shale appears Muddy and Obsidian appears Shiny. The luster of Shale is dull while that of Obsidian is vitreous. Shale is available in black, brown, buff, green, grey, red, yellow colors whereas Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors. The commercial uses of Shale are creating artwork, pottery and that of Obsidian are creating artwork, mirror, used in aquariums.