Picrite and Rhyolite
Definition
Definition
Picrite is a variety of high-magnesium olivine basalt that is very rich in the mineral olivine
Rhyolite is a fine-grained igneous rock which is rich in silica
History
Origin
Hawaii Islands
North America
Discoverer
Unknown
Ferdinand von Richthofen
Etymology
From Greek pikros bitter + -ite, 19th century
From German Rhyolit, from Greek rhuax lava stream + lithos stone
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
Family
Group
Volcanic
Volcanic
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock
Texture
Texture
Earthy, Rough
Aphanitic, Glassy, Porphyritic
Color
Black, Brown, Colourless, Green, Grey, Pink, White, Yellow
Grey, White, Light Black
Maintenance
Less
More
Durability
Durable
Durable
Water Resistant
Yes
Yes
Scratch Resistant
Yes
Yes
Stain Resistant
Yes
Yes
Wind Resistant
Yes
Yes
Acid Resistant
Yes
Yes
Appearance
Rough and Shiny
Banded
Uses
Architecture
Interior Uses
Countertops, Decorative Aggregates, Homes, Interior Decoration
Decorative Aggregates, Homes, Hotels, Interior Decoration, Kitchens
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
As Building Stone, As Facing Stone, Paving Stone, Office Buildings
Other Architectural Uses
Curbing
Not Yet Used
Industry
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.
Arrowheads, As Dimension Stone, Building houses or walls, Construction Aggregate, Cutting Tool, for Road Aggregate, Knives
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Monuments, Sculpture
Artifacts
Other Uses
Commercial Uses
As a Feed Additive for Livestock, As armour rock for sea walls, Metallurgical Flux, Pottery, Source of Magnesia (MgO)
Gemstone, Laboratory bench tops, Jewelry
Types
Types
Oceanite
Pumice Rocks, Obsidian Rocks, Perlite Rocks, Porphyritic Rocks.
Features
Host Rock for Lead
Acidic in nature, Available in lots of colors
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
Not Used
Petroglyphs
Not Used
Not Used
Figurines
Used
Not Yet Used
Fossils
Absent
Absent
Formation
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.
Rhyolite is a felsic extrusive rock and due to its high silica content, rhyolite lava is very viscous and is volcanic equivalent of granite.
Composition
Mineral Content
Biotite, Olivine, Plagioclase, Pyrrhotite
Biotite, Feldspar, Hornblade, Plagioclase, Pyroxene, Quartz
Compound Content
Al, CaO, Carbon Dioxide, Mg, MgO
Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide, Sodium
Transformation
Metamorphism
Yes
Yes
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Impact Metamorphism, Regional Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism
Weathering
Yes
Yes
Types of Weathering
Biological Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Erosion
Yes
Yes
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Chemical Erosion, Sea Erosion, Water Erosion, Wind Erosion
Properties
Physical Properties
Hardness
6.8
6-7
Grain Size
Fine Grained
Large and Coarse Grained
Fracture
Uneven
Sub-conchoidal
Streak
White, Greenish White or Grey
Colorless
Porosity
Less Porous
Highly Porous
Luster
Subvitreous to Dull
Earthy
Compressive Strength
189.00 N/mm2
11
140.00 N/mm2
15
Cleavage
Imperfect
Not Available
Toughness
2.1
2
Specific Gravity
2.75-2.92
2.65-2.67
Transparency
Opaque
Opaque
Density
1.5-2.5 g/cm3
2.4-2.6 g/cm3
Thermal Properties
Specific Heat Capacity
0.88 kJ/Kg K
13
Not Available
Resistance
Heat Resistant
Heat Resistant, Wear Resistant
Reserves
Deposits in Eastern Continents
Asia
India, Russia
China, India
Africa
South Africa
Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa
Europe
Iceland
Germany, Iceland, Ireland, Italy, Spain
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
Canada, USA
Canada, USA
South America
Brazil
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Deposits in Oceania Continent
Australia
Not Yet Found
New Zealand, Queensland, Western Australia
All about Picrite and Rhyolite Properties
Know all about Picrite and Rhyolite properties here. All properties of rocks are important as they define the type of rock and its application. Picrite and Rhyolite belong to Igneous Rocks.Texture of Picrite is Earthy, Rough whereas that of Rhyolite is Aphanitic, Glassy, Porphyritic. Picrite appears Rough and Shiny and Rhyolite appears Banded. The luster of Picrite is subvitreous to dull while that of Rhyolite is earthy. Picrite is available in black, brown, colourless, green, grey, pink, white, yellow colors whereas Rhyolite is available in grey, white, light black colors. The commercial uses of Picrite are as a feed additive for livestock, as armour rock for sea walls, metallurgical flux, pottery, source of magnesia (mgo) and that of Rhyolite are gemstone, laboratory bench tops, jewelry.
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