Definition
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
Amphibolite can be defined as a granular metamorphic rock which mainly consist of hornblende and plagioclase
Discoverer
Obsius
Alexandre Brongniart
Etymology
From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius
From Amphibole + -ite
Class
Igneous Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Group
Volcanic
Not Applicable
Other Categories
Opaque Rock
Coarse Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Glassy
Banded, Foliated, Massive
Color
Black, Blue, Brown, Green, Orange, Red, Tan, Yellow
Black, Brown, Green, Grey
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Shiny
Foliated
Interior Uses
Decorative Aggregates, Interior Decoration
Countertops, Decorative Aggregates, Entryways, Floor Tiles, Flooring, Homes, Hotels, Kitchens
Exterior Uses
Garden Decoration
As Building Stone, As Facing Stone, Paving Stone, Office Buildings
Other Architectural Uses
Not Yet Used
Curbing
Construction Industry
Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points
As Dimension Stone, Building houses or walls, Cobblestones, Construction Aggregate, for Road Aggregate, Landscaping, Production of Glass and Ceramics, Roadstone
Medical Industry
Surgery
Not Yet Used
Antiquity Uses
Artifacts, Jewellery
Artifacts, Sculpture, Small Figurines
Commercial Uses
Creating Artwork, Mirror, Used in aquariums
Cemetery Markers, Commemorative Tablets, Creating Artwork
Types
Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian
Hornblendite
Features
Blocks negativity, Helps to protect against depression
Clasts are smooth to touch, Matrix variable, Surfaces are often shiny
Archaeological Significance
Monuments
Not Yet Used
Used
Famous Monuments
Not Applicable
Data Not Available
Sculpture
Not Yet Used
Used
Famous Sculptures
Not Applicable
Data Not Available
Pictographs
Used
Not Used
Petroglyphs
Used
Not Used
Figurines
Not Yet Used
Used
Formation
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.
Amphibolite is a coarse-grained metamorphic rock which forms by metamorphism of mafic igneous rocks like basalt and gabbro or from the metamorphism of clay-rich sedimentary rocks like marl or graywacke.
Mineral Content
Not Available
Amphibole, Andalusite, Biotite, Calcite, Epidote, Garnet, Hornblade, Kyanite, Magnetite, Olivine, Plagioclase, Pyroxene, Staurolite, Wollastonite
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
Not Applicable
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Chemical Erosion, Glacier Erosion, Sea Erosion, Wind Erosion
Grain Size
Not Applicable
Medium to Coarse Grained
Fracture
Conchoidal
Irregular to Conchoidal
Streak
White
White to Grey
Porosity
Very Less Porous
Less Porous
Luster
Vitreous
Vitreous to Dull
Compressive Strength
Not Available
Cleavage
Non-Existent
Irregular
Toughness
Not Available
2.3
Specific Gravity
2.6-2.7
2.5
Transparency
Translucent
Opaque
Density
2.6 g/cm3
2.85-3.07 g/cm3
Specific Heat Capacity
Not Available
Resistance
Heat Resistant, Impact Resistant
Heat Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
Afghanistan, Indonesia, Japan, Russia
Russia, Turkey
Africa
Kenya
Burundi, Djibouti, Eritrea, Ethiopia, Kenya, Madagascar, Rwanda, Somalia, South Africa, Sudan, Tanzania, Uganda
Europe
Greece, Hungary, Iceland, Italy, Turkey
Germany, Greece, Iceland, Norway, Poland
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
Canada, Mexico, USA
Canada, USA
South America
Argentina, Chile, Ecuador, Peru
Brazil
Deposits in Oceania Continent
Australia
New Zealand
South Australia, Western Australia
All about Obsidian and Amphibolite Properties
Know all about Obsidian and Amphibolite properties here. All properties of rocks are important as they define the type of rock and its application. Obsidian belongs to Igneous Rocks while Amphibolite belongs to Metamorphic Rocks.Texture of Obsidian is Glassy whereas that of Amphibolite is Banded, Foliated, Massive. Obsidian appears Shiny and Amphibolite appears Foliated. The luster of Obsidian is vitreous while that of Amphibolite is vitreous to dull. Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors whereas Amphibolite is available in black, brown, green, grey colors. The commercial uses of Obsidian are creating artwork, mirror, used in aquariums and that of Amphibolite are cemetery markers, commemorative tablets, creating artwork.