Definition
Picrite is a variety of high-magnesium olivine basalt that is very rich in the mineral olivine
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
Origin
Hawaii Islands
New Zealand
Discoverer
Unknown
Unknown
Etymology
From Greek pikros bitter + -ite, 19th century
From German which means hornstone
Class
Igneous Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Soft Rock
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Earthy, Rough
Granular, Platy
Color
Black, Brown, Green, Grey, Pink, White, Yellow
Brown, Dark Greenish - Grey, Green, Reddish Brown
Durability
Durable
Durable
Appearance
Rough and Shiny
Dull
Interior Uses
Countertops, Decorative Aggregates, Homes, Interior Decoration
Decorative Aggregates, Flooring, Homes, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
Other Architectural Uses
Curbing
Curbing
Construction Industry
As a Sintering Agent in Steel Industry to process Iron Ore, Cement Manufacture, for Road Aggregate, Manufacture of Magnesium and Dolomite Refractories, Roadstone, Used for flooring, stair treads, borders and window sills.
for Road Aggregate, Roadstone
Antiquity Uses
Artifacts, Monuments, Sculpture
Artifacts, Monuments
Commercial Uses
As a Feed Additive for Livestock, As armour rock for sea walls, Metallurgical Flux, Pottery, Source of Magnesia (MgO)
Cemetery Markers, Commemorative Tablets, Creating Artwork
Types
Oceanite
Biotite hornfels
Features
Host Rock for Lead
Smooth to touch
Archaeological Significance
Formation
Picrite is a fine-grained, hard rock which is a type of metasomatite, essentially altered basalt. It forms with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.
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.
Mineral Content
Biotite, Olivine, Plagioclase, Pyrrhotite
Andalusite
Compound Content
Al, CaO, Carbon Dioxide, Mg, MgO
Fe, Mg
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Impact Metamorphism, Regional Metamorphism
-
Types of Weathering
Biological Weathering
Biological Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Chemical Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Grain Size
Fine Grained
Fine Grained
Fracture
Uneven
Conchoidal
Streak
White, Greenish White or Grey
-
Porosity
Less Porous
Highly Porous
Luster
Subvitreous to Dull
Shiny
Specific Gravity
2.75-2.92
3.4-3.9
Transparency
Opaque
Opaque
Density
1.5-2.5 g/cm3
0.25-0.30 g/cm3
Resistance
Heat Resistant
Heat Resistant, Impact Resistant, Pressure Resistant
Deposits in Eastern Continents
Asia
India, Russia
Bangladesh, Bhutan, China, India, North Korea, Qatar, Russia, Saudi Arabia, South Korea, Thailand
Africa
South Africa
Cameroon, East Africa, Tanzania, Western Africa
Europe
Iceland
United Kingdom
Deposits in Western Continents
North America
Canada, USA
Canada, USA
South America
Brazil
Bolivia, Brazil, Colombia, Ecuador
Deposits in Oceania Continent
Australia
-
New South Wales, New Zealand, Queensland, Western Australia
Picrite vs Hornfels 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. Picrite vs Hornfels characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Picrite and Properties of Hornfels. Learn more about Picrite vs Hornfels in the next section. The interior uses of Picrite include Countertops, Decorative aggregates, Homes and Interior decoration whereas the interior uses of Hornfels include Decorative aggregates, Flooring, Homes and Interior decoration. Due to some exceptional properties of Picrite and Hornfels, they have various applications in construction industry. The uses of Picrite in construction industry include As a sintering agent in steel industry to process iron ore, Cement manufacture, For road aggregate, Manufacture of magnesium and dolomite refractories, Roadstone, Used for flooring, stair treads, borders and window sills. and that of Hornfels include For road aggregate, Roadstone.
More about Picrite and Hornfels
Here you can know more about Picrite and Hornfels. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Picrite and Hornfels consists of mineral content and compound content. The mineral content of Picrite includes Biotite, Olivine, Plagioclase, Pyrrhotite and mineral content of Hornfels includes Andalusite. You can also check out the list of all Igneous Rocks. When we have to compare Picrite vs Hornfels, the texture, color and appearance plays an important role in determining the type of rock. Picrite is available in black, brown, green, grey, pink, white, yellow colors whereas, Hornfels is available in brown, dark greenish - grey, green, reddish brown colors. Appearance of Picrite is Rough and Shiny and that of Hornfels is Dull. Properties of rock is another aspect for Picrite vs Hornfels. The hardness of Picrite is 6.8 and that of Hornfels is 2-3. The types of Picrite are Oceanite whereas types of Hornfels are Biotite hornfels. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Picrite is white, greenish white or grey while that of Hornfels is . The specific heat capacity of Picrite is 0.88 kJ/Kg K and that of Hornfels is 0.84 kJ/Kg K. Depending on the properties like hardness, toughness, specific heat capacity, porosity etc., rocks are resistant to heat, wear, impact, etc.Picrite is heat resistant whereas Hornfels is heat resistant, impact resistant, pressure resistant.