Definition
Ijolite is an intrusive igneous rock which is composed mainly of nepheline and an alkali pyroxene, usually aegirine-augite
Argillites are highly compact sedimentary or slightly metamorphosed rocks that consist largely or wholly of particles of clay or silt but lack the fissility of shale or the cleavage characteristic of slate
Discoverer
Unknown
Unknown
Etymology
From the first syllable of the Finnish words Ii-vaara, Iijoki, &c. commonly used geographical names in Finland, and the Gr. Xiflos, a stone
From Latin Argilla (clay) and -ite in English which became agrilla+ -ite = Argillite
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Soft Rock
Other Categories
Coarse Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Earthy, Granular
Clastic, Polished
Color
Brown, Buff, Cream, Green, Grey, Pink, White
Dark Grey to Black, Pink, Red, White
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Banded and Foilated
Rough and Dull
Interior Uses
Decorative Aggregates, Entryways, Floor Tiles, Flooring, Homes, Interior Decoration, Kitchens
Decorative Aggregates, Homes, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
As Building Stone, Garden Decoration, Office Buildings
Other Architectural Uses
Curbing
Curbing, Whetstones
Construction Industry
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate, Landscaping, Making natural cement, Manufacture of Magnesium and Dolomite Refractories
Used for flooring, stair treads, borders and window sills.
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
Artifacts, Monuments, Sculpture
Commercial Uses
Cemetery Markers, Creating Artwork
Fire resistant, Used to manufracture paperweights and bookends
Types
Alkaline rock
Metamorphic rock
Features
Application of acids on the surface causes cloudy frosting, Available in Lots of Colors and Patterns, Is one of the oldest rock
Is one of the oldest rock
Archaeological Significance
Formation
Ijolite 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.
An argillite is a fine-grained sedimentary rock mainly composed of clay particles which forms from lithified muds which contain variable amounts of silt-sized particles.
Mineral Content
Albite, Amphibole, Biotite, Cancrinite, Feldspar, Hornblende, Plagioclase, Pyroxene, Sodalite
Biotite, Chlorite, Feldspar, Micas, Muscovite or Illite, Plagioclase, Pyrite, Quartz
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide
Iron(III) Oxide, Potassium Oxide, MgO, Silicon Dioxide
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
-
Types of Weathering
Biological Weathering, Chemical Weathering
Biological Weathering
Types of Erosion
Chemical Erosion, Water Erosion, Wind Erosion
Chemical Erosion
Grain Size
Coarse Grained
Fine Grained
Fracture
Conchoidal to Uneven
Conchoidal to Uneven
Streak
White
White to Grey
Porosity
Less Porous
Highly Porous
Luster
Greasy to Dull
Waxy and Dull
Specific Gravity
2.6-2.76
2.56-2.68
Transparency
Opaque
Opaque
Density
2.6 g/cm3
2.54-2.66 g/cm3
Resistance
Heat Resistant, Impact Resistant, Wear Resistant
Heat Resistant, Impact Resistant
Deposits in Eastern Continents
Asia
Indonesia, Iran, Russia, Saudi Arabia, Sri Lanka, Taiwan, Thailand, Turkey, Vietnam
Bangladesh, China, India, Russia
Africa
Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa
Ethiopia, Kenya, Morocco, South Africa, Tanzania
Europe
England, Finland, Germany, Great Britain, Greece, United Kingdom
Austria, France, Germany, Greece, Italy, Romania, Scotland, Spain, Switzerland
Deposits in Western Continents
North America
Canada, USA
USA
South America
Colombia
Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Deposits in Oceania Continent
Australia
New Zealand, Queensland, Western Australia
New South Wales, New Zealand, Queensland, Victoria, Western Australia