Definition
Tephrite is an aphanitic to porphyritic textured, volcanic igneous rock
Ijolite is an intrusive igneous rock which is composed mainly of nepheline and an alkali pyroxene, usually aegirine-augite
Origin
Germany
Finland, Europe
Discoverer
Van Tooren
Unknown
Etymology
From Greek tephra, ashes from Indo-European base, to burn
From the first syllable of the Finnish words Ii-vaara, Iijoki, &c. commonly used geographical names in Finland, and the Gr. Xiflos, a stone
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Other Categories
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock
Texture
Aphanitic to Porphyritic
Earthy, Granular
Color
Black, Brown, Green, Grey, White
Brown, Buff, Cream, Green, Grey, Pink, White
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Vesicular
Banded and Foilated
Interior Uses
Decorative Aggregates, Flooring, Homes, Interior Decoration
Decorative Aggregates, Entryways, Floor Tiles, Flooring, Homes, Interior Decoration, Kitchens
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
Other Architectural Uses
Curbing
Curbing
Construction Industry
Landscaping
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate, Landscaping, Making natural cement, Manufacture of Magnesium and Dolomite Refractories
Antiquity Uses
Artifacts, Sculpture
Artifacts, Monuments, Sculpture, Small Figurines
Commercial Uses
Production of Lime, Soil Conditioner
Cemetery Markers, Creating Artwork
Types
Igneous rock
Alkaline rock
Features
Host Rock for Lead
Application of acids on the surface causes cloudy frosting, Available in Lots of Colors and Patterns, Is one of the oldest rock
Archaeological Significance
Formation
Tephrite 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.
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.
Mineral Content
Alkali feldspar, Nepheline, Plagioclase, Pyroxene
Albite, Amphibole, Biotite, Cancrinite, Feldspar, Hornblende, Plagioclase, Pyroxene, Sodalite
Compound Content
CaO, Carbon Dioxide, MgO, Silicon Dioxide
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide
Types of Metamorphism
Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion
Chemical Erosion, Water Erosion, Wind Erosion
Grain Size
Medium to Fine Coarse Grained
Coarse Grained
Fracture
Uneven
Conchoidal to Uneven
Streak
Bluish Black
White
Porosity
Very Less Porous
Less Porous
Luster
Subvitreous to Dull
Greasy to Dull
Cleavage
Crenulation and Pervasive
-
Specific Gravity
2.86
2.6-2.76
Transparency
Opaque
Opaque
Density
2.8-2.9 g/cm3
2.6 g/cm3
Resistance
Heat Resistant, Impact Resistant
Heat Resistant, Impact Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
-
Indonesia, Iran, Russia, Saudi Arabia, Sri Lanka, Taiwan, Thailand, Turkey, Vietnam
Africa
Namibia, Uganda
Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa
Europe
Germany, Hungary, Italy, Portugal, Spain
England, Finland, Germany, Great Britain, Greece, United Kingdom
Deposits in Western Continents
North America
USA
Canada, USA
Deposits in Oceania Continent
Australia
New Zealand, Western Australia
New Zealand, Queensland, Western Australia