Definition
Hornfels is a metamorphic rock formed by the contact between mudstone or other clay rich rock, and a hot igneous body, and represents a heat altered equivalent of the original rock
Gritstone or grit is a hard, coarse-grained, siliceous sandstone
Origin
New Zealand
Pennines, England
Discoverer
Unknown
J.J. Ferber
Etymology
From German which means hornstone
From Grit + Stone
Class
Metamorphic Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Hard Rock
Group
Not Applicable
Not Applicable
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock
Texture
Granular, Platy
Earthy
Color
Brown, Dark Greenish - Grey, Green, Reddish Brown
Beige, Black, Brown, Colourless, Cream, Dark Brown, Green, Grey, Light Green, Light to Dark Grey, Pink, Red, White, Yellow
Durability
Durable
Durable
Appearance
Dull
Layered and Foliated
Interior Uses
Decorative Aggregates, Flooring, Homes, Interior Decoration
Countertops, Decorative Aggregates, Homes, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
As Building Stone, Garden Decoration, Office Buildings, Paving Stone
Other Architectural Uses
Curbing
Curbing
Construction Industry
for Road Aggregate, Roadstone
Construction Aggregate, Roadstone
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Monuments
Artifacts, Monuments, Sculpture
Commercial Uses
Cemetery Markers, Commemorative Tablets, Creating Artwork
An Oil and Gas Reservoir, As a Feed Additive for Livestock, Gemstone, Metallurgical Flux, Production of Lime, Soil Conditioner, Source of Magnesia (MgO), Tombstones
Types
Biotite hornfels
Not Available
Features
Smooth to touch
Available in Lots of Colors and Patterns, Generally rough to touch, Very fine grained rock
Archaeological Significance
Famous Monuments
Data Not Available
Data Not Available
Sculpture
Not Yet Used
Used
Famous Sculptures
Not Applicable
Data Not Available
Pictographs
Used
Not Used
Petroglyphs
Used
Not Used
Figurines
Not Yet Used
Used
Formation
Due to change in environmental conditions, rocks are heated and pressurized deep inside the Earth's surface. Hornfels is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.
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.
Mineral Content
Andalusite
Calcite, Clay Minerals, Feldspar, Micas, Quartz
Compound Content
Fe, Mg
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide
Types of Metamorphism
Not Applicable
Not Applicable
Types of Weathering
Biological Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Chemical Erosion, Coastal Erosion
Grain Size
Fine Grained
Coarse Grained
Fracture
Conchoidal
Conchoidal
Porosity
Highly Porous
Highly Porous
Toughness
Not Yet Found
Not Available
Specific Gravity
3.4-3.9
2.250
Transparency
Opaque
Opaque
Density
0.25-0.30 g/cm3
2.2 g/cm3
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant
Heat Resistant, Impact Resistant, Pressure Resistant
Deposits in Eastern Continents
Asia
Bangladesh, Bhutan, China, India, North Korea, Qatar, Russia, Saudi Arabia, South Korea, Thailand
China, India, Kazakhstan, Mongolia, Russia, Uzbekistan
Africa
Cameroon, East Africa, Tanzania, Western Africa
Namibia, Nigeria, South Africa
Europe
United Kingdom
Austria, Denmark, Germany, Great Britain, Netherlands, Poland, Sweden, Switzerland, United Kingdom
Others
Not Yet Found
Greenland
Deposits in Western Continents
North America
Canada, USA
Canada, USA
South America
Bolivia, Brazil, Colombia, Ecuador
Brazil
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Queensland, Western Australia
New South Wales, New Zealand, Western Australia
Hornfels vs Gritstone 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. Hornfels vs Gritstone characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Hornfels and Properties of Gritstone. Learn more about Hornfels vs Gritstone in the next section. The interior uses of Hornfels include Decorative aggregates, Flooring, Homes and Interior decoration whereas the interior uses of Gritstone include Countertops, Decorative aggregates, Homes and Interior decoration. Due to some exceptional properties of Hornfels and Gritstone, they have various applications in construction industry. The uses of Hornfels in construction industry include For road aggregate, Roadstone and that of Gritstone include Construction aggregate, Roadstone.
More about Hornfels and Gritstone
Here you can know more about Hornfels and Gritstone. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Hornfels and Gritstone consists of mineral content and compound content. The mineral content of Hornfels includes Andalusite and mineral content of Gritstone includes Calcite, Clay Minerals, Feldspar, Micas, Quartz. You can also check out the list of all Metamorphic Rocks. When we have to compare Hornfels vs Gritstone, the texture, color and appearance plays an important role in determining the type of rock. Hornfels is available in brown, dark greenish - grey, green, reddish brown colors whereas, Gritstone is available in beige, black, brown, colourless, cream, dark brown, green, grey, light green, light to dark grey, pink, red, white, yellow colors. Appearance of Hornfels is Dull and that of Gritstone is Layered and Foliated. Properties of rock is another aspect for Hornfels vs Gritstone. The hardness of Hornfels is 2-3 and that of Gritstone is 6-7. The types of Hornfels are Biotite hornfels whereas types of Gritstone are Not Available. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Hornfels is unknown while that of Gritstone is white. The specific heat capacity of Hornfels is 0.84 kJ/Kg K and that of Gritstone 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.Hornfels is heat resistant, impact resistant, pressure resistant whereas Gritstone is heat resistant, impact resistant, pressure resistant.
