Definition
Picrite is a variety of high-magnesium olivine basalt that is very rich in the mineral olivine
  
Comendite is a hard, peralkaline igneous rock, a type of light blue grey rhyolite
  
History
  
  
Origin
Hawaii Islands
  
Italy
  
Discoverer
Unknown
  
Unknown
  
Etymology
From Greek pikros bitter + -ite, 19th century
  
Comendite derives its name from the area of Le Commende on San Pietro Island in Italy
  
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
  
Medium Grained Rock, Opaque Rock
  
Texture
Earthy, Rough
  
Porphyritic
  
Color
Black, Brown, Colourless, Green, Grey, Pink, White, Yellow
  
Blue, Bluish - Grey
  
Maintenance
Less
  
Less
  
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
  
Foliated
  
Architecture
  
  
Interior Uses
Countertops, Decorative Aggregates, Homes, Interior Decoration
  
Countertops, Decorative Aggregates, Interior Decoration
  
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
  
As Building Stone, As Facing Stone, Garden Decoration
  
Other Architectural Uses
Curbing
  
Curbing
  
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.
  
Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate, Landscaping, Making natural cement, Raw material for the manufacture of mortar
  
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)
  
Cemetery Markers
  
Types
Oceanite
  
Rhyolite
  
Features
Host Rock for Lead
  
Very fine grained rock, It is One of the Oldest, Strongest and Hardest Rock
  
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
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.
  
Comendite is a type of Igneous rock which is formed due to cooling and solidification of lava or magma. It may form with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.
  
Composition
  
  
Mineral Content
Biotite, Olivine, Plagioclase, Pyrrhotite
  
Albite, Amphibole, Quartz
  
Compound Content
Al, CaO, Carbon Dioxide, Mg, MgO
  
Al, Fe, Potassium Oxide
  
Transformation
  
  
Metamorphism
Yes
  
Yes
  
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Impact Metamorphism, Regional 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
  
Coastal Erosion, Water Erosion
  
Physical Properties
  
  
Hardness
6.8
  
6-7
  
Grain Size
Fine Grained
  
Medium Grained
  
Fracture
Uneven
  
Pervasive
  
Streak
White, Greenish White or Grey
  
Bluish Black
  
Porosity
Less Porous
  
Highly Porous
  
Luster
Subvitreous to Dull
  
Dull
  
Compressive Strength
189.00 N/mm2
  
11
92.40 N/mm2
  
21
Cleavage
Imperfect
  
Not Available
  
Toughness
2.1
  
2
  
Specific Gravity
2.75-2.92
  
2.38
  
Transparency
Opaque
  
Opaque
  
Density
1.5-2.5 g/cm3
  
Not Available
  
Thermal Properties
  
  
Specific Heat Capacity
0.88 kJ/Kg K
  
13
Not Available
  
Resistance
Heat Resistant
  
Heat Resistant, Impact Resistant
  
Deposits in Eastern Continents
  
  
Asia
India, Russia
  
China
  
Africa
South Africa
  
East Africa
  
Europe
Iceland
  
Italy
  
Others
Not Yet Found
  
Not Yet Found
  
Deposits in Western Continents
  
  
North America
Canada, USA
  
Not Yet Found
  
South America
Brazil
  
Not Yet Found
  
Deposits in Oceania Continent
  
  
Australia
Not Yet Found
  
Queensland
  
All about Picrite and Comendite Properties
Know all about Picrite and Comendite properties here. All properties of rocks are important as they define the type of rock and its application. Picrite and Comendite belong to Igneous Rocks.Texture of Picrite is Earthy, Rough whereas that of Comendite is Porphyritic. Picrite appears Rough and Shiny and Comendite appears Foliated. The luster of Picrite is subvitreous to dull while that of Comendite is dull. Picrite is available in black, brown, colourless, green, grey, pink, white, yellow colors whereas Comendite is available in blue, bluish - grey 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 Comendite are cemetery markers.