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
Sandstone is defined as a rock which is composed of sand-sized grains of various minerals mostly of uniform size and often are smooth and rounded
History
Origin
Ethiopia
-
Discoverer
Obsius
Unknown
Etymology
From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius
From its composition, sand and stone
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Family
Group
Volcanic
-
Other Categories
Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Opaque Rock
Texture
Glassy
Clastic, Granular, Rough
Color
Black, Blue, Brown, Green, Orange, Red, Tan, Yellow
Beige, Black, Brown, Cream, Dark Brown, Green, Grey, Light Green, Light to Dark Grey, Pink, Red, White, Yellow
Maintenance
Less
More
Durability
Durable
Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Shiny
Rough
Architecture
Interior Uses
Decorative Aggregates, Interior Decoration
Countertops, Decorative Aggregates, Interior Decoration
Exterior Uses
Garden Decoration
As Building Stone, As Facing Stone, Office Buildings
Other Architectural Uses
-
Curbing
Industry
Construction Industry
Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points
Cement Manufacture, Construction Aggregate, for Road Aggregate, Production of Glass and Ceramics, Raw material for the manufacture of mortar
Medical Industry
Surgery
-
Antiquity Uses
Artifacts, Jewellery
Artifacts, Monuments, Sculpture
Other Uses
Commercial Uses
Creating Artwork, Mirror, Used in aquariums
An Oil and Gas Reservoir, In aquifers, Petroleum reservoirs, Soil Conditioner, Source of Magnesia (MgO), Tombstones, Used in aquariums
Types
Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian
Grey Sandstones, Crystallized Sandstones, Hard Sandstones , Carbonate Cemented Sandstones and Ganister
Features
Blocks negativity, Helps to protect against depression
Available in Lots of Colors and Patterns, Generally rough to touch, Very fine grained rock
Archaeological Significance
Monuments
-
-
Famous Monuments
-
Abu Simbel in Egypt, Agia Sophia in Istanbul, Turkey, Angkor Wat in Cambodia, Buland Darwaza in Agra, India, Chhatrapati Shivaji Terminus in Maharashtra, India, Dom in Berlin, Great Sphinx at Giza, Egypt, Hawa Mahal in Jaipur, India, Humayun's Tomb in Delhi, India, India Gate in Delhi, India, Jama Masjid in Delhi, India, Khajuraho Temples, India, Leh Palace in Leh, India, Lotus Temple in New Delhi, India, Luxor Temple in Egypt, Machu Picchu in Peru, Neuschwanstein in Bavaria, Petra in Jordan, Qutb Minar in India, Red Fort in Delhi, India, Sanchi Stupa in India
Sculpture
-
-
Famous Sculptures
-
Ajanta Caves in Maharashtra, India, Elephanta Caves in Maharashtra, India, Mount Rushmore National Memorial in South Dakota, US
Pictographs
-
-
Petroglyphs
-
-
Figurines
-
-
Fossils
Absent
Present
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.
Sandstone is a sedimentary rock which forms from cemented sand-sized clasts. It forms when sand layers are buried under sediments of sand.
Composition
Mineral Content
-
Calcite, Clay, Clay Minerals, Feldspar, Micas, Quartz
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide
Transformation
Metamorphism
✔
✘
✔
✘
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
-
Weathering
✔
✘
✔
✘
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Erosion
✔
✘
✔
✘
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Physical Properties
Hardness
5-5.56-7
1
7
👆🏻
Grain Size
-
Coarse or Fine
Fracture
Conchoidal
Conchoidal
Streak
White
White
Porosity
Very Less Porous
Highly Porous
Luster
Vitreous
Dull
Compressive Strength
0.15 N/mm295.00 N/mm2
0.15
450
👆🏻
Cleavage
-
Perfect
Toughness
-
2.6
Specific Gravity
2.6-2.72.2-2.8
0
8.4
👆🏻
Transparency
Translucent
Opaque
Density
2.6 g/cm32.2-2.8 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
0.92 kJ/Kg K0.92 kJ/Kg K
0.14
3.2
👆🏻
Resistance
Heat Resistant, Impact Resistant
Heat Resistant, Impact Resistant, Pressure Resistant
Deposits in Eastern Continents
Asia
Afghanistan, Indonesia, Japan, Russia
China, India, Kazakhstan, Mongolia, Russia, Thailand, Uzbekistan
Africa
Kenya
Namibia, Nigeria, South Africa
Europe
Greece, Hungary, Iceland, Italy, Turkey
Austria, Denmark, Germany, Great Britain, Netherlands, Norway, Poland, Sweden, Switzerland, United Kingdom
Others
-
Greenland
Deposits in Western Continents
North America
Canada, Mexico, USA
Canada, USA
South America
Argentina, Chile, Ecuador, Peru
Brazil
Deposits in Oceania Continent
Australia
New Zealand
New South Wales, New Zealand