Definition
Gritstone or grit is a hard, coarse-grained, siliceous sandstone
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
Origin
Pennines, England
Ethiopia
Discoverer
J.J. Ferber
Obsius
Etymology
From Grit + Stone
From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius
Class
Sedimentary Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Group
Not Applicable
Volcanic
Other Categories
Coarse Grained Rock, Opaque Rock
Opaque Rock
Color
Beige, Black, Brown, Colourless, Cream, Dark Brown, Green, Grey, Light Green, Light to Dark Grey, Pink, Red, White, Yellow
Black, Blue, Brown, Green, Orange, Red, Tan, Yellow
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Layered and Foliated
Shiny
Interior Uses
Countertops, Decorative Aggregates, Homes, Interior Decoration
Decorative Aggregates, Interior Decoration
Exterior Uses
As Building Stone, Garden Decoration, Office Buildings, Paving Stone
Garden Decoration
Other Architectural Uses
Curbing
Not Yet Used
Construction Industry
Construction Aggregate, Roadstone
Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points
Medical Industry
Not Yet Used
Surgery
Antiquity Uses
Artifacts, Monuments, Sculpture
Artifacts, Jewellery
Commercial Uses
An Oil and Gas Reservoir, As a Feed Additive for Livestock, Gemstone, Metallurgical Flux, Production of Lime, Soil Conditioner, Source of Magnesia (MgO), Tombstones
Creating Artwork, Mirror, Used in aquariums
Types
Not Available
Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian
Features
Available in Lots of Colors and Patterns, Generally rough to touch, Very fine grained rock
Blocks negativity, Helps to protect against depression
Archaeological Significance
Monuments
Used
Not Yet Used
Famous Monuments
Data Not Available
Not Applicable
Sculpture
Used
Not Yet Used
Famous Sculptures
Data Not Available
Not Applicable
Pictographs
Not Used
Used
Petroglyphs
Not Used
Used
Figurines
Used
Not Yet Used
Formation
Gritstone is a type of sedimentary rock which was formed on the floors of wide river deltas where the grit deposits were laid down, with every tide or flood dumping another layer of sediment.
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
Calcite, Clay Minerals, Feldspar, Micas, Quartz
Not Available
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide
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
Chemical Erosion, Coastal Erosion, Glacier Erosion
Grain Size
Coarse Grained
Not Applicable
Fracture
Conchoidal
Conchoidal
Porosity
Highly Porous
Very Less Porous
Cleavage
Perfect
Non-Existent
Toughness
Not Available
Not Available
Specific Gravity
2.250
2.6-2.7
Transparency
Opaque
Translucent
Density
2.2 g/cm3
2.6 g/cm3
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant
Heat Resistant, Impact Resistant
Deposits in Eastern Continents
Asia
China, India, Kazakhstan, Mongolia, Russia, Uzbekistan
Afghanistan, Indonesia, Japan, Russia
Africa
Namibia, Nigeria, South Africa
Kenya
Europe
Austria, Denmark, Germany, Great Britain, Netherlands, Poland, Sweden, Switzerland, United Kingdom
Greece, Hungary, Iceland, Italy, Turkey
Others
Greenland
Not Yet Found
Deposits in Western Continents
North America
Canada, USA
Canada, Mexico, USA
South America
Brazil
Argentina, Chile, Ecuador, Peru
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Western Australia
New Zealand
All about Gritstone and Obsidian Properties
Know all about Gritstone and Obsidian properties here. All properties of rocks are important as they define the type of rock and its application. Gritstone belongs to Sedimentary Rocks while Obsidian belongs to Igneous Rocks.Texture of Gritstone is Earthy whereas that of Obsidian is Glassy. Gritstone appears Layered and Foliated and Obsidian appears Shiny. The luster of Gritstone is dull while that of Obsidian is vitreous. Gritstone is available in beige, black, brown, colourless, cream, dark brown, green, grey, light green, light to dark grey, pink, red, white, yellow colors whereas Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors. The commercial uses of Gritstone are an oil and gas reservoir, as a feed additive for livestock, gemstone, metallurgical flux, production of lime, soil conditioner, source of magnesia (mgo), tombstones and that of Obsidian are creating artwork, mirror, used in aquariums.