Definition
Rhomb-porphyry is a porphyritic igneous rock with abundant wedge or lens shaped anorthoclase or feldspar phenocrysts
  
Ignimbrite is a volcanic rock consisting mainly of pumice fragments, formed by the consolidation of material deposited by pyroclastic flows
  
History
  
  
Origin
Unknown
  
New Zealand
  
Discoverer
Unknown
  
Patrick Marshall
  
Etymology
From Latin term that means purple
  
From Latin ignis fire + imber, imbr- shower of rain, storm cloud + -ite
  
Class
Igneous Rocks
  
Igneous Rocks
  
Sub-Class
Durable Rock, Medium Hardness Rock
  
Durable Rock, Medium Hardness Rock
  
Family
  
  
Group
Volcanic
  
Volcanic
  
Other Categories
Fine Grained Rock, Opaque Rock
  
Fine Grained Rock, Opaque Rock
  
Texture
Aphanitic to Porphyritic
  
Aphanitic
  
Color
Black, Brown, Colourless, Green, Grey, Pink, White
  
Beige, Black, Brown, Grey, Pink, White
  
Maintenance
Less
  
More
  
Durability
Durable
  
Durable
  
Water Resistant
Yes
  
Yes
  
Scratch Resistant
No
  
Yes
  
Stain Resistant
Yes
  
No
  
Wind Resistant
Yes
  
Yes
  
Acid Resistant
No
  
No
  
Appearance
Rough
  
Dull, Vesicular and Foilated
  
Architecture
  
  
Interior Uses
Decorative Aggregates, Homes, Interior Decoration
  
Decorative Aggregates, Floor Tiles, Homes, Interior Decoration
  
Exterior Uses
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration, Office Buildings
  
As Building Stone, Garden Decoration, Office Buildings, Paving Stone
  
Other Architectural Uses
Curbing
  
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
  
Building houses or walls, Construction Aggregate
  
Medical Industry
Not Yet Used
  
Not Yet Used
  
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
  
Artifacts, Monuments, Sculpture, Small Figurines
  
Other Uses
  
  
Commercial Uses
An Oil and Gas Reservoir, As a Feed Additive for Livestock, Metallurgical Flux, Soil Conditioner, Source of Magnesia (MgO)
  
Cemetery Markers, Commemorative Tablets, Creating Artwork
  
Types
Not Available
  
Not Available
  
Features
Host Rock for Lead
  
Always found as volcanic pipes over deep continental crust
  
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
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.
  
Ignimbrites are formed from very poorly sorted mixture of volcanic ash or tuff and pumice lapilli, commonly with scattered lithic fragments.
  
Composition
  
  
Mineral Content
Alkali feldspar, Biotite, Plagioclase, Pyroxene
  
Apatite, Biotite, Calcite, Chlorite, Feldspar, Hematite, Hornblade, Ilmenite, Magnetite, Olivine, Pyroxene, Quartz
  
Compound Content
CaO, Cl, MgO
  
Ca, NaCl
  
Transformation
  
  
Metamorphism
Yes
  
Yes
  
Types of Metamorphism
Impact Metamorphism
  
Burial Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
  
Weathering
Yes
  
Yes
  
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
  
Biological Weathering, Chemical Weathering
  
Erosion
Yes
  
Yes
  
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Water Erosion
  
Chemical Erosion, Coastal Erosion
  
Physical Properties
  
  
Hardness
5-5.5
  
4-6
  
Grain Size
Fine Grained
  
Fine Grained
  
Fracture
Conchoidal
  
Uneven
  
Streak
White
  
White
  
Porosity
Very Less Porous
  
Highly Porous
  
Luster
Subvitreous to Dull
  
Vitreous to Dull
  
Compressive Strength
310.00 N/mm2
  
2
243.80 N/mm2
  
5
Cleavage
Perfect
  
Not Available
  
Toughness
2.7
  
Not Available
  
Specific Gravity
2.86
  
2.73
  
Transparency
Translucent
  
Opaque
  
Density
2.8-2.9 g/cm3
  
1-1.8 g/cm3
  
Thermal Properties
  
  
Specific Heat Capacity
0.92 kJ/Kg K
  
10
0.20 kJ/Kg K
  
25
Resistance
Heat Resistant, Pressure Resistant
  
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
  
Deposits in Eastern Continents
  
  
Asia
Not Yet Found
  
Afghanistan, Armenia, Azerbaijan, Burma, Cambodia, China, India, Indonesia, Iran, Japan, Malaysia, Mongolia, Nepal, North Korea, Pakistan, Saudi Arabia, Syria, Taiwan, Thailand, Turkey, Vietnam, Yemen
  
Africa
Not Yet Found
  
Cameroon, Cape Verde, Chad, Djibouti, Eritrea, Ethiopia, Kenya, Libya, Madagascar, Nigeria, Rwanda, South Africa, Sudan, Tanzania, Uganda
  
Europe
Bulgaria
  
France, Georgia, Germany, Greece, Iceland, Italy, Netherlands, Poland, Portugal, Spain, United Kingdom
  
Others
Not Yet Found
  
Antarctica, Hawaii Islands
  
Deposits in Western Continents
  
  
North America
USA
  
Canada, Costa Rica, Panama, USA
  
South America
Not Yet Found
  
Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador
  
Deposits in Oceania Continent
  
  
Australia
Not Yet Found
  
Central Australia, Western Australia