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
Other Categories
Coarse Grained Rock, Opaque Rock
Opaque Rock
Color
Beige, Black, Brown, 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
-
Construction Industry
Construction Aggregate, Roadstone
Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points
Medical Industry
-
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
Sedimentary rock
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
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
-
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
-
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
-
Fracture
Conchoidal
Conchoidal
Porosity
Highly Porous
Very Less Porous
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
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
Gritstone vs Obsidian Characteristics
Though some rocks look identical, they have certain characteristics which distinguish them from others. Characteristics of rocks include texture, appearance, color, fracture, streak, hardness etc. Gritstone vs Obsidian characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Gritstone and Properties of Obsidian. Learn more about Gritstone vs Obsidian in the next section. The interior uses of Gritstone include Countertops, Decorative aggregates, Homes and Interior decoration whereas the interior uses of Obsidian include Decorative aggregates and Interior decoration. Due to some exceptional properties of Gritstone and Obsidian, they have various applications in construction industry. The uses of Gritstone in construction industry include Construction aggregate, Roadstone and that of Obsidian include Arrowheads, Cutting tool, Knives, Scrapers, Spear points.
More about Gritstone and Obsidian
Here you can know more about Gritstone and Obsidian. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Gritstone and Obsidian consists of mineral content and compound content. The mineral content of Gritstone includes Calcite, Clay Minerals, Feldspar, Micas, Quartz and mineral content of Obsidian includes . You can also check out the list of all Sedimentary Rocks. When we have to compare Gritstone vs Obsidian, the texture, color and appearance plays an important role in determining the type of rock. Gritstone is available in beige, black, brown, 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. Appearance of Gritstone is Layered and Foliated and that of Obsidian is Shiny. Properties of rock is another aspect for Gritstone vs Obsidian. The hardness of Gritstone is 6-7 and that of Obsidian is 5-5.5. The types of Gritstone are Sedimentary rock whereas types of Obsidian are Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Gritstone and Obsidian is white. The specific heat capacity of Gritstone is 0.92 kJ/Kg K and that of Obsidian is 0.92 kJ/Kg K. Depending on the properties like hardness, toughness, specific heat capacity, porosity etc., rocks are resistant to heat, wear, impact, etc.Gritstone is heat resistant, impact resistant, pressure resistant whereas Obsidian is heat resistant, impact resistant.