1 Definition
1.1 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
Shale is a fine-grained sedimentary rock which is formed by the compaction of silt and clay-size mineral particles
1.2 History
1.2.1 Origin
1.2.2 Discoverer
1.3 Etymology
From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius
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,
1.4 Class
Igneous Rocks
Sedimentary Rocks
1.4.1 Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Medium Hardness Rock
1.5 Family
1.5.1 Group
1.6 Other Categories
Opaque Rock
Fine Grained Rock, Opaque Rock
2 Texture
2.1 Texture
Glassy
Clastic, Splintery
2.2 Color
Black, Blue, Brown, Green, Orange, Red, Tan, Yellow
Black, Brown, Buff, Green, Grey, Red, Yellow
2.3 Maintenance
2.4 Durability
2.4.1 Water Resistant
2.4.2 Scratch Resistant
2.4.3 Stain Resistant
2.4.4 Wind Resistant
2.4.5 Acid Resistant
2.5 Appearance
3 Uses
3.1 Architecture
3.1.1 Interior Uses
Decorative Aggregates, Interior Decoration
Decorative Aggregates, Homes, Interior Decoration
3.1.2 Exterior Uses
Garden Decoration
As Building Stone, As Facing Stone, Office Buildings
3.1.3 Other Architectural Uses
3.2 Industry
3.2.1 Construction Industry
Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points
Cement Manufacture, Construction Aggregate, for Road Aggregate, Making natural cement, Raw material for the manufacture of mortar
3.2.2 Medical Industry
3.3 Antiquity Uses
Artifacts, Jewellery
Artifacts, Sculpture
3.4 Other Uses
3.4.1 Commercial Uses
Creating Artwork, Mirror, Used in aquariums
Creating Artwork, Pottery
4 Types
4.1 Types
Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian
Red Shale, Black Shale, Green Shale, Grey Shale and Yellow Shale
4.2 Features
Blocks negativity, Helps to protect against depression
Easily splits into thin plates, Generally rough to touch, Very fine grained rock
4.3 Archaeological Significance
4.3.1 Monuments
4.3.2 Famous Monuments
Not Applicable
Jantar Mantar in India
4.3.3 Sculpture
4.3.4 Famous Sculptures
Not Applicable
Data Not Available
4.3.5 Pictographs
4.3.6 Petroglyphs
4.3.7 Figurines
4.4 Fossils
5 Formation
5.1 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.
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.
5.2 Composition
5.2.1 Mineral Content
Not Available
Albite, Biotite, Calcite, Chert, Chlorite, Dolomite, Hematite, Micas, Muscovite or Illite, Pyrite, Quartz, Silica, Sulfides
5.2.2 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
5.3 Transformation
5.3.1 Metamorphism
5.3.2 Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
Not Applicable
5.3.3 Weathering
5.3.4 Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
5.3.5 Erosion
5.3.6 Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
6 Properties
6.1 Physical Properties
6.1.1 Hardness
6.1.2 Grain Size
Not Applicable
Very fine-grained
6.1.3 Fracture
6.1.4 Streak
6.1.5 Porosity
Very Less Porous
Highly Porous
6.1.6 Luster
6.1.7 Compressive Strength
0.15 N/mm295.00 N/mm2
0.15
450
6.1.8 Cleavage
6.1.9 Toughness
6.1.10 Specific Gravity
6.1.11 Transparency
6.1.12 Density
2.6 g/cm32.4-2.8 g/cm3
0
1400
6.2 Thermal Properties
6.2.1 Specific Heat Capacity
0.92 kJ/Kg K0.39 kJ/Kg K
0.14
3.2
6.2.2 Resistance
Heat Resistant, Impact Resistant
Heat Resistant, Impact Resistant
7 Reserves
7.1 Deposits in Eastern Continents
7.1.1 Asia
Afghanistan, Indonesia, Japan, Russia
Bangladesh, China, India, Russia
7.1.2 Africa
Kenya
Ethiopia, Kenya, Morocco, South Africa, Tanzania
7.1.3 Europe
Greece, Hungary, Iceland, Italy, Turkey
Austria, France, Germany, Greece, Italy, Romania, Scotland, Spain, Switzerland
7.1.4 Others
Not Yet Found
Not Yet Found
7.2 Deposits in Western Continents
7.2.1 North America
7.2.2 South America
Argentina, Chile, Ecuador, Peru
Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
7.3 Deposits in Oceania Continent
7.3.1 Australia
New Zealand
New South Wales, New Zealand, Queensland, Victoria, Western Australia