Definition
Diabase is a fine-grained igneous rock which is composed mostly of pyroxene and feldspar
  
Tephrite is an aphanitic to porphyritic textured, volcanic igneous rock
  
History
  
  
Origin
Germany
  
Germany
  
Discoverer
Christian Leopold von Buch
  
Van Tooren
  
Etymology
From Greek di + base
  
From Greek tephra, ashes from Indo-European base, to burn
  
Class
Igneous Rocks
  
Igneous Rocks
  
Sub-Class
Durable Rock, Hard Rock
  
Durable Rock, Hard Rock
  
Family
  
  
Group
Volcanic
  
Volcanic
  
Other Categories
Fine Grained Rock, Medium Grained Rock, Opaque Rock
  
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
  
Texture
Aphanitic, Granular
  
Aphanitic to Porphyritic
  
Color
Dark Grey to Black
  
Black, Brown, Colourless, Green, Grey, White
  
Maintenance
Less
  
Less
  
Durability
Durable
  
Durable
  
Water Resistant
Yes
  
Yes
  
Scratch Resistant
Yes
  
Yes
  
Stain Resistant
Yes
  
No
  
Wind Resistant
Yes
  
Yes
  
Acid Resistant
Yes
  
No
  
Appearance
Vesicular
  
Vesicular
  
Architecture
  
  
Interior Uses
Countertops, Decorative Aggregates, Homes, Interior Decoration, Kitchens
  
Decorative Aggregates, Flooring, Homes, Interior Decoration
  
Exterior Uses
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration, Office Buildings
  
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings
  
Other Architectural Uses
Curbing
  
Curbing
  
Industry
  
  
Construction Industry
As Dimension Stone, Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate
  
Landscaping
  
Medical Industry
Not Yet Used
  
Not Yet Used
  
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
  
Artifacts, Sculpture
  
Other Uses
  
  
Commercial Uses
An Oil and Gas Reservoir, Cemetery Markers, Commemorative Tablets, Laboratory bench tops, Jewelry, Sea Defence, Tombstones
  
Production of Lime, Soil Conditioner
  
Types
Not Available
  
Not Available
  
Features
Smooth to touch
  
Host Rock for Lead
  
Archaeological Significance
  
  
Monuments
Used
  
Not Yet Used
  
Famous Monuments
Stonehenge in English county of Wiltshire
  
Not Applicable
  
Sculpture
Used
  
Used
  
Famous Sculptures
Data Not Available
  
Data Not Available
  
Pictographs
Not Used
  
Not Used
  
Petroglyphs
Not Used
  
Not Used
  
Figurines
Used
  
Used
  
Fossils
Absent
  
Absent
  
Formation
Diabase forms when molten igneous rock is squeezed up into a vertical crack in other rocks, the crack is usually forced apart and the molten rock cools in the space to form a tabular igneous intrusion cutting across the surrounding rocks and is known as a dike.
  
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.
  
Composition
  
  
Mineral Content
Augite, Chlorite, Olivine, Plagioclase, Pyroxene, Pyrrhotite, Serpentine
  
Alkali feldspar, Nepheline, Plagioclase, Pyroxene
  
Compound Content
Aluminium Oxide, CaO, Chromium(III) Oxide, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Sulfur Trioxide
  
CaO, Carbon Dioxide, MgO, Silicon Dioxide
  
Transformation
  
  
Metamorphism
Yes
  
Yes
  
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Regional Metamorphism
  
Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism
  
Weathering
Yes
  
Yes
  
Types of Weathering
Biological Weathering, Chemical Weathering
  
Biological Weathering, Chemical Weathering, Mechanical Weathering
  
Erosion
Yes
  
Yes
  
Types of Erosion
Chemical Erosion, Coastal Erosion, Water Erosion
  
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion
  
Physical Properties
  
  
Hardness
7
  
6.5
  
Grain Size
Fine to Medium Grained
  
Medium to Fine Coarse Grained
  
Fracture
Conchoidal
  
Uneven
  
Streak
Black
  
Bluish Black
  
Porosity
Highly Porous
  
Very Less Porous
  
Luster
Not Available
  
Subvitreous to Dull
  
Compressive Strength
225.00 N/mm2
  
7
90.00 N/mm2
  
22
Cleavage
Not Available
  
Crenulation and Pervasive
  
Toughness
1.6
  
2.4
  
Specific Gravity
2.86-2.87
  
2.86
  
Transparency
Opaque
  
Opaque
  
Density
2.7-3.3 g/cm3
  
2.8-2.9 g/cm3
  
Thermal Properties
  
  
Specific Heat Capacity
Not Available
  
0.92 kJ/Kg K
  
10
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
  
Heat Resistant, Impact Resistant
  
Deposits in Eastern Continents
  
  
Asia
India
  
Not Yet Found
  
Africa
South Africa, Tanzania
  
Namibia, Uganda
  
Europe
Germany, Greece, Italy, Scotland, Turkey
  
Germany, Hungary, Italy, Portugal, Spain
  
Others
Antarctica, Greenland
  
Not Yet Found
  
Deposits in Western Continents
  
  
North America
Canada, USA
  
USA
  
South America
Argentina, Brazil, Colombia, Venezuela
  
Not Yet Found
  
Deposits in Oceania Continent
  
  
Australia
Central Australia, New Zealand, Queensland, Western Australia
  
New Zealand, Western Australia