Definition
Ignimbrite is a volcanic rock consisting mainly of pumice fragments, formed by the consolidation of material deposited by pyroclastic flows
Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers called coal beds
Discoverer
Patrick Marshall
John Peter Salley
Etymology
From Latin ignis fire + imber, imbr- shower of rain, storm cloud + -ite
From the Old English term col, which has meant mineral of fossilized carbon since the 13th century
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Soft Rock
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Aphanitic
Amorphous, Glassy
Color
Beige, Black, Brown, Grey, Pink, White
Black, Brown, Dark Brown, Grey, Light to Dark Grey
Durability
Durable
Durable
Appearance
Dull, Vesicular and Foilated
Veined or Pebbled
Interior Uses
Decorative Aggregates, Floor Tiles, Homes, Interior Decoration
-
Exterior Uses
As Building Stone, Garden Decoration, Office Buildings, Paving Stone
-
Other Architectural Uses
Curbing
-
Construction Industry
Building houses or walls, Construction Aggregate
Cement Manufacture, for Road Aggregate, Making natural cement, Steel Production
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
Artifacts
Commercial Uses
Cemetery Markers, Commemorative Tablets, Creating Artwork
Alumina Refineries, Electricity Generation, Liquid Fuel, Manufacture of Soap, Solvents, Dyes, Plastics and Fibres, Paper Industry
Types
Pyroclastic rock
Peat, Lignite, Sub-Bituminous Coal, Bituminous Coal, Anthracite, Graphite
Features
Always found as volcanic pipes over deep continental crust
Helps in production of Heat and Electricity, Used as fossil fuel
Archaeological Significance
Formation
Ignimbrites are formed from very poorly sorted mixture of volcanic ash or tuff and pumice lapilli, commonly with scattered lithic fragments.
Coal forms from the accumulation of plant debris in a swamp environment which is buried by sediments such as mud or sand and then compacted to form coal.
Mineral Content
Apatite, Biotite, Calcite, Chlorite, Feldspar, Hematite, Hornblade, Ilmenite, Magnetite, Olivine, Pyroxene, Quartz
Analcime, Apatite, Barite, Calcite, Chalcopyrite, Chlorite, Chromite, Clausthalite, Clay Minerals, Crandallite Group, Dolomite, Feldspar, Galena, Gypsum, Marcasite, Muscovite or Illite, Pyrite, Quartz, Siderite, Sphalerite, Zircon
Compound Content
Ca, NaCl
Carbon, Hydrogen, Nitrogen, Oxygen, Sulphur
Types of Metamorphism
Burial Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering
-
Types of Erosion
Chemical Erosion, Coastal Erosion
-
Grain Size
Fine Grained
Medium to Fine Coarse Grained
Fracture
Uneven
Conchoidal
Porosity
Highly Porous
Less Porous
Luster
Vitreous to Dull
Dull to Vitreous to Submetallic
Specific Gravity
2.73
1.1-1.4
Transparency
Opaque
Opaque
Density
1-1.8 g/cm3
1100-1400 g/cm3
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant
Deposits in Eastern Continents
Asia
Afghanistan, Armenia, Azerbaijan, Burma, Cambodia, China, India, Indonesia, Iran, Japan, Malaysia, Mongolia, Nepal, North Korea, Pakistan, Saudi Arabia, Syria, Taiwan, Thailand, Turkey, Vietnam, Yemen
Bangladesh, Burma, Cambodia, China, India, Indonesia, Kazakhstan, Malaysia, Mongolia, Pakistan, Turkey, Vietnam
Africa
Cameroon, Cape Verde, Chad, Djibouti, Eritrea, Ethiopia, Kenya, Libya, Madagascar, Nigeria, Rwanda, South Africa, Sudan, Tanzania, Uganda
Botswana, Kenya, Morocco, Mozambique, South Africa, Tanzania
Europe
France, Georgia, Germany, Greece, Iceland, Italy, Netherlands, Poland, Portugal, Spain, United Kingdom
Belgium, Bulgaria, England, France, Germany, Greece, Hungary, Kosovo, Netherlands, Norway, Poland, Romania, Serbia, Slovakia, Slovenia, The Czech Republic, Ukraine, United Kingdom
Others
Antarctica, Hawaii Islands
-
Deposits in Western Continents
North America
Canada, Costa Rica, Panama, USA
Canada, Mexico, USA
South America
Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador
Brazil, Chile, Colombia, Venezuela
Deposits in Oceania Continent
Australia
Central Australia, Western Australia
New South Wales, Queensland, Victoria