1 Definition
1.1 Definition
Tephrite is an aphanitic to porphyritic textured, volcanic igneous rock
Chert is a hard, dark, opaque sedimentary rock which is composed of silica with an amorphous fine-grained texture
1.2 History
1.2.1 Origin
1.2.2 Discoverer
1.3 Etymology
From Greek tephra, ashes from Indo-European base, to burn
From flint-like quartz, 1670s, of unknown origin- a local term, which has been taken into geological use
1.4 Class
Igneous Rocks
Sedimentary Rocks
1.4.1 Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
1.5 Family
1.5.1 Group
1.6 Other Categories
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
2 Texture
2.1 Texture
Aphanitic to Porphyritic
Banded, Rough
2.2 Color
Black, Brown, Colourless, Green, Grey, White
Black, Brown, Green, Grey, Red, White
2.3 Maintenance
2.4 Durability
2.4.1 Water Resistant
2.4.2 Scratch Resistant
2.4.3 Stain Resistant
2.4.4 Wind Resistant
2.4.5 Acid Resistant
2.5 Appearance
Vesicular
Glassy or Pearly
3 Uses
3.1 Architecture
3.1.1 Interior Uses
Decorative Aggregates, Flooring, Homes, Interior Decoration
Decorative Aggregates, Homes
3.1.2 Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings
3.1.3 Other Architectural Uses
3.2 Industry
3.2.1 Construction Industry
Landscaping
Arrowheads, Construction Aggregate, Cutting Tool, Spear Points
3.2.2 Medical Industry
Not Yet Used
Not Yet Used
3.3 Antiquity Uses
Artifacts, Sculpture
Artifacts, Monuments
3.4 Other Uses
3.4.1 Commercial Uses
Production of Lime, Soil Conditioner
Creating Artwork, Gemstone, In fire-starting tools, Jewelry, To ignite fire, Used in flintlock firearms
4 Types
4.1 Types
Not Available
Flint, Jasper, Radiolarite, Common Chert, Chalcedony, Agate, Onyx, Opal, Magadi-type Chert, Porcelanite, Siliceous Sinter
4.2 Features
Host Rock for Lead
Clasts are smooth to touch, Easily splits into thin plates, Has High structural resistance against erosion and climate
4.3 Archaeological Significance
4.3.1 Monuments
4.3.2 Famous Monuments
Not Applicable
Data Not Available
4.3.3 Sculpture
4.3.4 Famous Sculptures
Data Not Available
Not Applicable
4.3.5 Pictographs
4.3.6 Petroglyphs
4.3.7 Figurines
4.4 Fossils
5 Formation
5.1 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.
Chert forms when microcrystals of silicon dioxide grow within soft sediments that become limestone or chalk. The chert formation can be either of chemical or biological origin.
5.2 Composition
5.2.1 Mineral Content
Alkali feldspar, Nepheline, Plagioclase, Pyroxene
Quartz, Silicon
5.2.2 Compound Content
CaO, Carbon Dioxide, MgO, Silicon Dioxide
Silicon Dioxide
5.3 Transformation
5.3.1 Metamorphism
5.3.2 Types of Metamorphism
Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism
Not Applicable
5.3.3 Weathering
5.3.4 Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Not Applicable
5.3.5 Erosion
5.3.6 Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion
Chemical Erosion
6 Properties
6.1 Physical Properties
6.1.1 Hardness
6.1.2 Grain Size
Medium to Fine Coarse Grained
Very fine-grained
6.1.3 Fracture
Uneven
Uneven, Splintery or Conchoidal
6.1.4 Streak
6.1.5 Porosity
Very Less Porous
Highly Porous
6.1.6 Luster
Subvitreous to Dull
Waxy and Dull
6.1.7 Compressive Strength
90.00 N/mm2450.00 N/mm2
0.15
450
6.1.8 Cleavage
Crenulation and Pervasive
Non-Existent
6.1.9 Toughness
6.1.10 Specific Gravity
6.1.11 Transparency
Opaque
Translucent to Opaque
6.1.12 Density
2.8-2.9 g/cm32.7 g/cm3
0
1400
6.2 Thermal Properties
6.2.1 Specific Heat Capacity
0.92 kJ/Kg K0.74 kJ/Kg K
0.14
3.2
6.2.2 Resistance
Heat Resistant, Impact Resistant
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
7 Reserves
7.1 Deposits in Eastern Continents
7.1.1 Asia
Not Yet Found
China, India, Iran, Japan, Oman, Russia, Saudi Arabia, Taiwan, Thailand, Vietnam
7.1.2 Africa
Namibia, Uganda
Kenya, Morocco, South Africa, Tanzania
7.1.3 Europe
Germany, Hungary, Italy, Portugal, Spain
Austria, France, Greece, Italy, Malta, Poland, Portugal, Serbia, Spain, Sweden, United Kingdom
7.1.4 Others
Not Yet Found
Greenland, Mid-Atlantic Ridge
7.2 Deposits in Western Continents
7.2.1 North America
7.2.2 South America
Not Yet Found
Bolivia, Brazil
7.3 Deposits in Oceania Continent
7.3.1 Australia
New Zealand, Western Australia
New South Wales, Queensland, South Australia, Western Australia