Definition
Rhomb-porphyry is a porphyritic igneous rock with abundant wedge or lens shaped anorthoclase or feldspar phenocrysts
Schist is a medium grade metamorphic rock with medium to large, flat, sheet like grains in a preferred orientation
History
Origin
-
-
Discoverer
Unknown
Unknown
Etymology
From Latin term that means purple
From French schiste, Greek skhistos i.e. split
Class
Igneous Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Medium Hardness Rock
Family
Group
Volcanic
-
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Aphanitic to Porphyritic
Foliated, Platy
Color
Black, Brown, Green, Grey, Pink, White
Black, Blue, Brown, Dark Brown, Green, Grey, Silver
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Rough
Layered and Shiny
Architecture
Interior Uses
Decorative Aggregates, Homes, Interior Decoration
Decorative Aggregates, Floor Tiles, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration, Office Buildings
Garden Decoration, Paving Stone
Other Architectural Uses
Curbing
-
Industry
Construction Industry
As a Flux in the Production of Steel and Pig Iron, As a Sintering Agent in Steel Industry to process Iron Ore, As Dimension Stone, Cement Manufacture, for Road Aggregate, Making natural cement, Manufacture of Magnesium and Dolomite Refractories
As Dimension Stone, Building houses or walls, Cement Manufacture, for Road Aggregate, Roadstone
Medical Industry
-
-
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
Artifacts
Other Uses
Commercial Uses
An Oil and Gas Reservoir, As a Feed Additive for Livestock, Metallurgical Flux, Soil Conditioner, Source of Magnesia (MgO)
Used in aquariums, Writing Slates
Types
Igneous rock
Mica Schists, Calc-Silicate Schists, Graphite Schists, Blueschists, Whiteschists, Greenschists, Hornblende Schist, Talc Schist, Chlorite Schist, Garnet Schist, Glaucophane schist.
Features
Host Rock for Lead
Easily splits into thin plates, Smooth to touch
Archaeological Significance
Monuments
-
-
Famous Monuments
-
-
Sculpture
-
-
Famous Sculptures
-
-
Pictographs
-
-
Petroglyphs
-
-
Figurines
-
-
Fossils
Absent
Absent
Formation
Rhomb-porphyry 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.
Schist formed by dynamic metamorphism at high temperatures and pressures that aligns the grains of mica, hornblende and other elongated minerals into thin layers.
Composition
Mineral Content
Alkali feldspar, Biotite, Plagioclase, Pyroxene
Alusite, Amphibole, Biotite, Chlorite, Epidote, Feldspar, Garnet, Graphite, Hornblade, Kyanite, Micas, Muscovite or Illite, Porphyroblasts, Quartz, Sillimanite, Staurolite, Talc
Compound Content
CaO, Cl, MgO
CaO, Carbon Dioxide, MgO
Transformation
Metamorphism
✔
✘
✔
✘
Types of Metamorphism
Impact Metamorphism
-
Weathering
✔
✘
✔
✘
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Erosion
✔
✘
✔
✘
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Water Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Physical Properties
Hardness
5-5.53.5-4
1
7
👆🏻
Grain Size
Fine Grained
Medium to Fine Coarse Grained
Fracture
Conchoidal
Conchoidal
Streak
White
White
Porosity
Very Less Porous
Highly Porous
Luster
Subvitreous to Dull
Shiny
Compressive Strength
310.00 N/mm2150.00 N/mm2
0.15
450
👆🏻
Cleavage
Perfect
Slaty
Toughness
2.7
1.5
Specific Gravity
2.862.5-2.9
0
8.4
👆🏻
Transparency
Translucent
Opaque
Density
2.8-2.9 g/cm32.8-2.9 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
0.92 kJ/Kg K0.70 kJ/Kg K
0.14
3.2
👆🏻
Resistance
Heat Resistant, Pressure Resistant
Impact Resistant, Pressure Resistant, Water Resistant
Deposits in Eastern Continents
Asia
-
Afghanistan, Bangladesh, Bhutan, China, India, Japan, Kazakhstan, Malaysia, Pakistan, Russia, Thailand, Turkey, Vietnam
Africa
-
Egypt, Ethiopia, Morocco, Nigeria, South Africa
Europe
Bulgaria
Austria, England, France, Georgia, Germany, Italy, Liechtenstein, Monaco, Norway, Slovenia, Spain, Sweden, Switzerland
Others
-
-
Deposits in Western Continents
North America
USA
Canada, Costa Rica, Cuba, Mexico, Panama, USA
South America
-
Brazil, Colombia, Guyana
Deposits in Oceania Continent
Australia
-
New South Wales, New Zealand, Queensland