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
Pegmatite rock is a holocrystalline, intrusive igneous rock which is composed of interlocking phaneritic crystals
Discoverer
Obsius
R. J. Hauy
Etymology
From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius
From Greek pegma, pegmat which means- thing joined together + -ite
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Other Categories
Opaque Rock
Coarse Grained Rock, Opaque Rock
Texture
Glassy
Pegmatitic
Color
Black, Blue, Brown, Green, Orange, Red, Tan, Yellow
Black, Brown, Cream, Green, Grey, Pink, Red, Rust, Silver, White, Yellow
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Shiny
Layered, Banded, Veined and Shiny
Interior Uses
Decorative Aggregates, Interior Decoration
Decorative Aggregates, Flooring, Interior Decoration
Exterior Uses
Garden Decoration
As Building Stone, As Facing Stone, Paving Stone
Other Architectural Uses
Not Yet Used
Curbing
Construction Industry
Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points
As Dimension Stone, Building houses or walls, Construction Aggregate, for Road Aggregate, Landscaping
Medical Industry
Surgery
Not Yet Used
Antiquity Uses
Artifacts, Jewellery
Artifacts, Sculpture, Small Figurines
Commercial Uses
Creating Artwork, Mirror, Used in aquariums
Creating Artwork, Jewelry, Source of corundum, tourmalines, beryls and topaz
Types
Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian
Granite Pegmatite, Gabbro Pegmatite and Diorite Pegmatite
Features
Blocks negativity, Helps to protect against depression
Generally rough to touch, Is one of the oldest rock, Source of corundum, tourmalines, beryls and topaz
Archaeological Significance
Monuments
Not Yet Used
Not Yet Used
Famous Monuments
Not Applicable
Not Applicable
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.
Pegmatite rock is holocrystalline, intrusive igneous rock which is formed by partial melting and dewatering during the process of metamorphism.
Mineral Content
Not Available
Apatite, Beryl, Feldspar, Fluorite, Garnet, Lepidolite, Quartz, Silica, Spodumene, Topaz
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, Magnesium Carbonate, MgO, Phosphorus Pentoxide
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Grain Size
Not Applicable
Medium to Coarse Grained
Fracture
Conchoidal
Conchoidal
Porosity
Very Less Porous
Less Porous
Luster
Vitreous
Grainy, Pearly and Vitreous
Cleavage
Non-Existent
Perfect
Toughness
Not Available
2.1
Specific Gravity
2.6-2.7
2.6-2.63
Transparency
Translucent
Translucent to Opaque
Density
2.6 g/cm3
2.6-2.65 g/cm3
Specific Heat Capacity
Not Available
Resistance
Heat Resistant, Impact Resistant
Heat Resistant, Impact Resistant, Pressure Resistant
Deposits in Eastern Continents
Asia
Afghanistan, Indonesia, Japan, Russia
China, India, Iran, Japan, Nepal, North Korea, Russia, Saudi Arabia, South Korea
Africa
Kenya
South Africa
Europe
Greece, Hungary, Iceland, Italy, Turkey
Austria, France, Greece, Ireland, Italy, Netherlands, Slovakia, Spain, Turkey, Ukraine
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
Canada, Mexico, USA
Canada
South America
Argentina, Chile, Ecuador, Peru
Brazil
Deposits in Oceania Continent
Australia
New Zealand
New South Wales, Queensland, South Australia, Western Australia
All about Obsidian and Pegmatite Properties
Know all about Obsidian and Pegmatite properties here. All properties of rocks are important as they define the type of rock and its application. Obsidian and Pegmatite belong to Igneous Rocks.Texture of Obsidian is Glassy whereas that of Pegmatite is Pegmatitic. Obsidian appears Shiny and Pegmatite appears Layered, Banded, Veined and Shiny. The luster of Obsidian is vitreous while that of Pegmatite is grainy, pearly and vitreous. Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors whereas Pegmatite is available in black, brown, cream, green, grey, pink, red, rust, silver, white, yellow colors. The commercial uses of Obsidian are creating artwork, mirror, used in aquariums and that of Pegmatite are creating artwork, jewelry, source of corundum, tourmalines, beryls and topaz.