Definition
Hawaiite is volcanic rock that resembles basalt. It is an olivine basalt with intermediate composition between alkali olivine and mugearite
Tephrite is an aphanitic to porphyritic textured, volcanic igneous rock
History
Origin
Hawaii Islands
Germany
Discoverer
Joseph Iddings
Van Tooren
Etymology
From Hawaii Islands
From Greek tephra, ashes from Indo-European base, to burn
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Family
Group
Volcanic
Volcanic
Other Categories
Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Glassy, Massive, Porphyritic, Scoriaceous, Vesicular
Aphanitic to Porphyritic
Color
Black, Brown, Light to Dark Grey
Black, Brown, Green, Grey, White
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Dull and Soft
Vesicular
Architecture
Interior Uses
Decorative Aggregates, Floor Tiles, Flooring, Homes, Hotels, 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, Cobblestones, Rail Track Ballast, Roadstone
Landscaping
Medical Industry
-
-
Antiquity Uses
Artifacts
Artifacts, Sculpture
Other Uses
Commercial Uses
Creating Artwork, Sea Defence
Production of Lime, Soil Conditioner
Types
Volcanic rock
Igneous rock
Features
Has High structural resistance against erosion and climate, Very fine grained rock
Host Rock for Lead
Archaeological Significance
Monuments
-
-
Famous Monuments
Easter Island in the Polynesian Triangle, Pacific Ocean
-
Sculpture
-
-
Famous Sculptures
-
-
Pictographs
-
-
Petroglyphs
-
-
Figurines
-
-
Fossils
Absent
Absent
Formation
Hawaiite is a fine-grained, hard rock that forms when bits of lava shoot out of volcanoes and reach the Earth's surface.
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
Olivine, Plagioclase, Pyroxene
Alkali feldspar, Nepheline, Plagioclase, Pyroxene
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
CaO, Carbon Dioxide, MgO, Silicon Dioxide
Transformation
Metamorphism
✔
✘
✔
✘
Types of Metamorphism
Impact Metamorphism
Cataclastic Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism
Weathering
✔
✘
✔
✘
Types of Weathering
Biological Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Erosion
✔
✘
✔
✘
Types of Erosion
-
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion
Physical Properties
Hardness
66.5
1
7
👆🏻
Grain Size
-
Medium to Fine Coarse Grained
Fracture
Conchoidal
Uneven
Streak
-
Bluish Black
Porosity
Less Porous
Very Less Porous
Luster
-
Subvitreous to Dull
Compressive Strength
37.40 N/mm290.00 N/mm2
0.15
450
👆🏻
Cleavage
-
Crenulation and Pervasive
Toughness
-
2.4
Specific Gravity
-99992.86
0
8.4
👆🏻
Transparency
Opaque
Opaque
Density
-9999 g/cm32.8-2.9 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
0.84 kJ/Kg K0.92 kJ/Kg K
0.14
3.2
👆🏻
Resistance
Heat Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Impact Resistant
Deposits in Eastern Continents
Asia
India, Russia
-
Africa
South Africa
Namibia, Uganda
Europe
Iceland
Germany, Hungary, Italy, Portugal, Spain
Others
Hawaii Islands
-
Deposits in Western Continents
North America
Canada, USA
USA
South America
Brazil
-
Deposits in Oceania Continent
Australia
-
New Zealand, Western Australia