Definition
Very fine grained fault rock which is composed of glassy matrix that often contains inclusions of wall-rock fragments.
  
Harzburgite is a plutonic rock of the peridotite group consisting largely of orthopyroxene and olivine
  
History
  
  
Origin
USA
  
Germany
  
Discoverer
Unknown
  
Unknown
  
Etymology
From pseudo- + tachylite, a glassy rock generated by frictional heat within faults.
  
From the name of a town in Harzburg, Germany
  
Class
Metamorphic Rocks
  
Igneous Rocks
  
Sub-Class
Durable Rock, Hard Rock
  
Durable Rock, Medium Hardness Rock
  
Family
  
  
Group
Not Applicable
  
Plutonic
  
Other Categories
Fine Grained Rock, Opaque Rock
  
Coarse Grained Rock, Opaque Rock
  
Texture
Quench
  
Phaneritic
  
Color
Black, Brown, Colourless, Green, Grey, Pink, White
  
Dark Greenish - Grey
  
Maintenance
Less
  
Less
  
Durability
Durable
  
Durable
  
Water Resistant
Yes
  
Yes
  
Scratch Resistant
Yes
  
Yes
  
Stain Resistant
No
  
Yes
  
Wind Resistant
Yes
  
Yes
  
Acid Resistant
Yes
  
No
  
Appearance
Dull and Soft
  
Rough and Shiny
  
Architecture
  
  
Interior Uses
Decorative Aggregates, Entryways, Interior Decoration
  
Decorative Aggregates, Homes, Interior Decoration
  
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration
  
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
  
Other Architectural Uses
Curbing
  
Curbing
  
Industry
  
  
Construction Industry
As Dimension Stone, Cement Manufacture, for Road Aggregate, Making natural cement
  
As Dimension Stone, Cobblestones
  
Medical Industry
Not Yet Used
  
Not Yet Used
  
Antiquity Uses
Artifacts, Monuments
  
Artifacts, Monuments, Sculpture, Small Figurines
  
Other Uses
  
  
Commercial Uses
Creating Artwork, Gemstone
  
Creating Artwork, Gemstone, Jewelry, Source of Chromite, Platinum, Nickel and Garnet, Source of Diamonds
  
Types
Not Available
  
Not Available
  
Features
Host Rock for Lead
  
Constitutes upper part of the Earth's mantle, Generally rough to touch, Is one of the oldest rock
  
Archaeological Significance
  
  
Monuments
Used
  
Used
  
Famous Monuments
Data Not Available
  
Data Not Available
  
Sculpture
Not Yet Used
  
Used
  
Famous Sculptures
Not Applicable
  
Data Not Available
  
Pictographs
Not Used
  
Used
  
Petroglyphs
Not Used
  
Used
  
Figurines
Not Yet Used
  
Used
  
Fossils
Absent
  
Absent
  
Formation
Due to change in environmental conditions, rocks are heated and pressurized deep inside the Earth's surface. Pseudotachylite is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.
  
Harzburgite 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
Iron Oxides, Pyroxene, Quartz, Stishovite, Sulfides
  
Amphibole, Chromite, Garnet, Magnesium, Olivine, Phlogopite, Plagioclase, Pyroxene
  
Compound Content
Carbon Dioxide, Silicon Dioxide, Sulfur Dioxide, Sulphur
  
Ca, Fe, Mg, Potassium, Silicon Dioxide, Sodium, Titanium Dioxide
  
Transformation
  
  
Metamorphism
Yes
  
Yes
  
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
  
Impact Metamorphism
  
Weathering
No
  
Yes
  
Types of Weathering
Not Applicable
  
Chemical Weathering, Mechanical Weathering
  
Erosion
No
  
Yes
  
Types of Erosion
Not Applicable
  
Chemical Erosion, Sea Erosion
  
Physical Properties
  
  
Hardness
7
  
5.5-6
  
Grain Size
Very fine-grained
  
Coarse Grained
  
Fracture
Uneven
  
Irregular
  
Streak
Light to dark brown
  
White
  
Porosity
Less Porous
  
Less Porous
  
Luster
Vitreous
  
Shiny
  
Compressive Strength
60.00 N/mm
2
  
25
Not Available
  
Cleavage
Irregular
  
Imperfect
  
Toughness
Not Available
  
2.1
  
Specific Gravity
2.46-2.86
  
3-3.01
  
Transparency
Transparent to Translucent
  
Translucent to Opaque
  
Density
2.7-2.9 g/cm3
  
3.1-3.4 g/cm3
  
Thermal Properties
  
  
Specific Heat Capacity
0.92 kJ/Kg K
  
10
1.25 kJ/Kg K
  
6
Resistance
Heat Resistant
  
Heat Resistant, Pressure Resistant, Wear Resistant
  
Deposits in Eastern Continents
  
  
Asia
South Korea
  
Japan, Oman
  
Africa
Western Africa
  
South Africa
  
Europe
Great Britain, Switzerland
  
France, Germany, Italy, Venezuela
  
Others
Not Yet Found
  
Hawaii Islands, Mid-Atlantic Ridge
  
Deposits in Western Continents
  
  
North America
Not Yet Found
  
Canada, USA
  
South America
Not Yet Found
  
Not Yet Found
  
Deposits in Oceania Continent
  
  
Australia
Central Australia, Western Australia
  
Not Yet Found