Definition
Harzburgite is a plutonic rock of the peridotite group consisting largely of orthopyroxene and olivine
Obsidian is a naturally occurring volcanic glass formed as an extrusive igneous rock. It is produced when felsic lava extruded from a volcano cools rapidly with minimum crystal growth
History
Origin
Germany
Ethiopia
Discoverer
Unknown
Obsius
Etymology
From the name of a town in Harzburg, Germany
From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Medium Hardness Rock
Family
Group
Plutonic
Volcanic
Other Categories
Coarse Grained Rock, Opaque Rock
Opaque Rock
Texture
Phaneritic
Glassy
Color
Dark Greenish - Grey
Black, Blue, Brown, Green, Orange, Red, Tan, Yellow
Maintenance
Less
Less
Durability
Durable
Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Rough and Shiny
Shiny
Architecture
Interior Uses
Decorative Aggregates, Homes, Interior Decoration
Decorative Aggregates, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
Garden Decoration
Other Architectural Uses
Curbing
-
Industry
Construction Industry
As Dimension Stone, Cobblestones
Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points
Medical Industry
-
Surgery
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
Artifacts, Jewellery
Other Uses
Commercial Uses
Creating Artwork, Gemstone, Jewelry, Source of Chromite, Platinum, Nickel and Garnet, Source of Diamonds
Creating Artwork, Mirror, Used in aquariums
Types
Ultramafic rock
Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian
Features
Constitutes upper part of the Earth's mantle, Generally rough to touch, Is one of the oldest rock
Blocks negativity, Helps to protect against depression
Archaeological Significance
Monuments
-
-
Famous Monuments
-
-
Sculpture
-
-
Famous Sculptures
-
-
Pictographs
-
-
Petroglyphs
-
-
Figurines
-
-
Fossils
Absent
Absent
Formation
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.
When the lava is released from volcano, it undergoes a very rapid cooling which freezes the mechanisms of crystallization. The result is a volcanic glass with a uniform smooth texture.
Composition
Mineral Content
Amphibole, Chromite, Garnet, Magnesium, Olivine, Phlogopite, Plagioclase, Pyroxene
-
Compound Content
Ca, Fe, Mg, Potassium, Silicon Dioxide, Sodium, Titanium Dioxide
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Transformation
Metamorphism
✔
✘
✔
✘
Types of Metamorphism
Impact Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
Weathering
✔
✘
✔
✘
Types of Weathering
Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Erosion
✔
✘
✔
✘
Types of Erosion
Chemical Erosion, Sea Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Physical Properties
Hardness
5.5-65-5.5
1
7
👆🏻
Grain Size
Coarse Grained
-
Fracture
Irregular
Conchoidal
Streak
White
White
Porosity
Less Porous
Very Less Porous
Luster
Shiny
Vitreous
Compressive Strength
150.00 N/mm20.15 N/mm2
0.15
450
👆🏻
Cleavage
-
-
Toughness
2.1
-
Specific Gravity
3-3.012.6-2.7
0
8.4
👆🏻
Transparency
Translucent to Opaque
Translucent
Density
3.1-3.4 g/cm32.6 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
1.25 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
Japan, Oman
Afghanistan, Indonesia, Japan, Russia
Africa
South Africa
Kenya
Europe
France, Germany, Italy
Greece, Hungary, Iceland, Italy, Turkey
Others
Hawaii Islands, Mid-Atlantic Ridge
-
Deposits in Western Continents
North America
Canada, USA
Canada, Mexico, USA
South America
-
Argentina, Chile, Ecuador, Peru
Deposits in Oceania Continent
Australia
-
New Zealand