Definition
Chalk is a soft, white, powdery limestone consisting mainly of fossil shells of foraminifers
  
Rhomb-porphyry is a porphyritic igneous rock with abundant wedge or lens shaped anorthoclase or feldspar phenocrysts
  
History
  
  
Discoverer
Unknown
  
Unknown
  
Etymology
From old English cealc chalk, lime, plaster; pebble, from Greek khalix small pebble, in English transferred to the opaque, white, soft limestone
  
From Latin term that means purple
  
Class
Sedimentary Rocks
  
Igneous Rocks
  
Sub-Class
Durable Rock, Soft Rock
  
Durable Rock, Medium Hardness Rock
  
Family
  
  
Group
Not Applicable
  
Volcanic
  
Other Categories
Fine Grained Rock, Opaque Rock
  
Fine Grained Rock, Opaque Rock
  
Texture
Clastic or Non-Clastic
  
Aphanitic to Porphyritic
  
Color
Grey, White, Yellow
  
Black, Brown, Colourless, Green, Grey, Pink, White
  
Maintenance
Less
  
Less
  
Durability
Durable
  
Durable
  
Water Resistant
No
  
Yes
  
Scratch Resistant
No
  
No
  
Stain Resistant
No
  
Yes
  
Wind Resistant
No
  
Yes
  
Acid Resistant
No
  
No
  
Appearance
Soft
  
Rough
  
Architecture
  
  
Interior Uses
Decorative Aggregates, Homes, Interior Decoration
  
Decorative Aggregates, Homes, Interior Decoration
  
Exterior Uses
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration
  
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration, Office Buildings
  
Other Architectural Uses
Powder
  
Curbing
  
Industry
  
  
Construction Industry
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate, Making natural cement, raw material for manufacture of quicklime and slaked lime, Source of calcium
  
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
  
Medical Industry
Not Yet Used
  
Not Yet Used
  
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
  
Artifacts, Monuments, Sculpture, Small Figurines
  
Other Uses
  
  
Commercial Uses
Alumina Refineries, Creating Artwork, Drawing on blackboards, Gymnasts, athletes and mountain climbers use for grip, In aquifers, Paper Industry, Production of Lime, Raw material for manufacture of quicklime, slaked lime, Soil Conditioner, Whiting, Whiting material in toothpaste, paint and paper
  
An Oil and Gas Reservoir, As a Feed Additive for Livestock, Metallurgical Flux, Soil Conditioner, Source of Magnesia (MgO)
  
Types
Not Available
  
Not Available
  
Features
Clasts are smooth to touch, Is one of the oldest rock, Smooth to touch, Very fine grained rock
  
Host Rock for Lead
  
Archaeological Significance
  
  
Monuments
Used
  
Used
  
Famous Monuments
Data Not Available
  
Data Not Available
  
Sculpture
Used
  
Used
  
Famous Sculptures
Data Not Available
  
Data Not Available
  
Pictographs
Used
  
Used
  
Petroglyphs
Used
  
Used
  
Figurines
Used
  
Used
  
Fossils
Present
  
Absent
  
Formation
Chalk is formed from lime mud, which accumulates on the sea floor which is then transformed into rock by geological processes.
  
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.
  
Composition
  
  
Mineral Content
Calcite, Clay, Clay Minerals, Quartz, Sand
  
Alkali feldspar, Biotite, Plagioclase, Pyroxene
  
Compound Content
Ca, NaCl, CaO
  
CaO, Cl, MgO
  
Transformation
  
  
Metamorphism
No
  
Yes
  
Types of Metamorphism
Not Applicable
  
Impact Metamorphism
  
Weathering
Yes
  
Yes
  
Types of Weathering
Biological Weathering, Chemical Weathering
  
Biological Weathering, Chemical Weathering, Mechanical Weathering
  
Erosion
Yes
  
Yes
  
Types of Erosion
Chemical Erosion, Coastal Erosion, Water Erosion
  
Chemical Erosion, Coastal Erosion, Glacier Erosion, Water Erosion
  
Physical Properties
  
  
Hardness
1
  
5-5.5
  
Grain Size
Very fine-grained
  
Fine Grained
  
Fracture
Not Available
  
Conchoidal
  
Streak
White
  
White
  
Porosity
Highly Porous
  
Very Less Porous
  
Luster
Dull
  
Subvitreous to Dull
  
Compressive Strength
Not Available
  
310.00 N/mm
2
  
2
Cleavage
Non-Existent
  
Perfect
  
Toughness
1
  
2.7
  
Specific Gravity
2.3-2.4
  
2.86
  
Transparency
Opaque
  
Translucent
  
Density
2.49-2.50 g/cm3
  
2.8-2.9 g/cm3
  
Thermal Properties
  
  
Specific Heat Capacity
0.90 kJ/Kg K
  
12
0.92 kJ/Kg K
  
10
Resistance
Heat Resistant
  
Heat Resistant, Pressure Resistant
  
Deposits in Eastern Continents
  
  
Asia
Brunei, India, Indonesia, Malaysia, Singapore, Thailand, Vietnam
  
Not Yet Found
  
Africa
Cameroon, Chad, Ghana, Kenya, Malawi, Sudan, Tanzania, Togo, Zambia, Zimbabwe
  
Not Yet Found
  
Europe
England, France, Germany, Spain, United Kingdom
  
Bulgaria
  
Others
Not Yet Found
  
Not Yet Found
  
Deposits in Western Continents
  
  
North America
Canada, USA
  
USA
  
South America
Colombia
  
Not Yet Found
  
Deposits in Oceania Continent
  
  
Australia
Adelaide, New Zealand, Queensland, Tonga, Victoria, Yorke Peninsula
  
Not Yet Found
  
Chalk vs Rhomb Porphyry 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. Chalk vs Rhomb Porphyry characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Chalk and Properties of Rhomb Porphyry. Learn more about Chalk vs Rhomb Porphyry in the next section. The interior uses of Chalk include Decorative aggregates, Homes and Interior decoration whereas the interior uses of Rhomb Porphyry include Decorative aggregates, Homes and Interior decoration. Due to some exceptional properties of Chalk and Rhomb Porphyry, they have various applications in construction industry. The uses of Chalk in construction industry include As dimension stone, Cement manufacture, Construction aggregate, For road aggregate, Making natural cement, Raw material for manufacture of quicklime and slaked lime, Source of calcium and that of Rhomb Porphyry include 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.
More about Chalk and Rhomb Porphyry
Here you can know more about Chalk and Rhomb Porphyry. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Chalk and Rhomb Porphyry consists of mineral content and compound content. The mineral content of Chalk includes Calcite, Clay, Clay Minerals, Quartz, Sand and mineral content of Rhomb Porphyry includes Alkali feldspar, Biotite, Plagioclase, Pyroxene. You can also check out the list of all Sedimentary Rocks. When we have to compare Chalk vs Rhomb Porphyry, the texture, color and appearance plays an important role in determining the type of rock. Chalk is available in grey, white, yellow colors whereas, Rhomb Porphyry is available in black, brown, colourless, green, grey, pink, white colors. Appearance of Chalk is Soft and that of Rhomb Porphyry is Rough. Properties of rock is another aspect for Chalk vs Rhomb Porphyry. The hardness of Chalk is 1 and that of Rhomb Porphyry is 5-5.5. The types of Chalk are Not Available whereas types of Rhomb Porphyry are Not Available. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Chalk and Rhomb Porphyry is white. The specific heat capacity of Chalk is 0.90 kJ/Kg K and that of Rhomb Porphyry 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.Chalk is heat resistant whereas Rhomb Porphyry is heat resistant, pressure resistant.