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
History
Origin
Ethiopia
Discoverer
Obsius
Etymology
From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius
Class
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Family
Group
Volcanic
Other Categories
Opaque Rock
Texture
Glassy
Color
Black, Blue, Brown, Green, Orange, Red, Tan, Yellow
Maintenance
Less
Durability
Durable
Water Resistant
✔
✘
81% - Igneous Rocks Rocks have it !
Scratch Resistant
✔
✘
86% - Igneous Rocks Rocks have it !
Stain Resistant
✔
✘
66% - Igneous Rocks Rocks
Wind Resistant
✔
✘
49% - Igneous Rocks Rocks
Acid Resistant
✔
✘
48% - Igneous Rocks Rocks
Appearance
Shiny
Architecture
Interior Uses
Decorative Aggregates, Interior Decoration
Exterior Uses
Garden Decoration
Other Architectural Uses
-
Industry
Construction Industry
Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points
Medical Industry
Surgery
Antiquity Uses
Artifacts, Jewellery
Other Uses
Commercial Uses
Creating Artwork, Mirror, Used in aquariums
Types
Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian
Features
Blocks negativity, Helps to protect against depression
Archaeological Significance
Monuments
-
Famous Monuments
-
Sculpture
-
Famous Sculptures
-
Pictographs
-
Petroglyphs
-
Figurines
-
Fossils
Absent
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.
Composition
Mineral Content
-
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Transformation
Metamorphism
✔
✘
97% - Igneous Rocks Rocks have it !
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
Weathering
✔
✘
99% - Igneous Rocks Rocks have it !
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Erosion
✔
✘
92% - Igneous Rocks Rocks have it !
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Physical Properties
Hardness
5-5.5
1
7
👆🏻
Grain Size
-
Fracture
Conchoidal
Streak
White
Porosity
Very Less Porous
Luster
Vitreous
Compressive Strength
0.15 N/mm2
Rank: 49 (Overall)
0.15
450
👆🏻
Cleavage
-
Toughness
-
Specific Gravity
2.6-2.7
0
8.4
👆🏻
Transparency
Translucent
Density
2.6 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
0.92 kJ/Kg K
Rank: 10 (Overall)
0.14
3.2
👆🏻
Resistance
Heat Resistant, Impact Resistant
Deposits in Eastern Continents
Asia
Afghanistan, Indonesia, Japan, Russia
Africa
Kenya
Europe
Greece, Hungary, Iceland, Italy, Turkey
Others
-
Deposits in Western Continents
North America
Canada, Mexico, USA
South America
Argentina, Chile, Ecuador, Peru
Deposits in Oceania Continent
Australia
New Zealand