Definition
Pegmatite rock is a holocrystalline, intrusive igneous rock which is composed of interlocking phaneritic crystals
Very fine grained fault rock which is composed of glassy matrix that often contains inclusions of wall-rock fragments.
Discoverer
R. J. Hauy
Unknown
Etymology
From Greek pegma, pegmat which means- thing joined together + -ite
From pseudo- + tachylite, a glassy rock generated by frictional heat within faults.
Class
Igneous Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
Group
Plutonic
Not Applicable
Other Categories
Coarse Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Pegmatitic
Quench
Color
Black, Brown, Cream, Green, Grey, Pink, Red, Rust, Silver, White, Yellow
Black, Brown, Colourless, Green, Grey, Pink, White
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Layered, Banded, Veined and Shiny
Dull and Soft
Interior Uses
Decorative Aggregates, Flooring, Interior Decoration
Decorative Aggregates, Entryways, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Paving Stone
As Building Stone, As Facing Stone, Garden Decoration
Other Architectural Uses
Curbing
Curbing
Construction Industry
As Dimension Stone, Building houses or walls, Construction Aggregate, for Road Aggregate, Landscaping
As Dimension Stone, Cement Manufacture, for Road Aggregate, Making natural cement
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts, Sculpture, Small Figurines
Artifacts, Monuments
Commercial Uses
Creating Artwork, Jewelry, Source of corundum, tourmalines, beryls and topaz
Creating Artwork, Gemstone
Types
Granite Pegmatite, Gabbro Pegmatite and Diorite Pegmatite
Not Available
Features
Generally rough to touch, Is one of the oldest rock, Source of corundum, tourmalines, beryls and topaz
Host Rock for Lead
Archaeological Significance
Monuments
Not Yet Used
Used
Famous Monuments
Not Applicable
Data Not Available
Sculpture
Used
Not Yet Used
Famous Sculptures
Data Not Available
Not Applicable
Pictographs
Not Used
Not Used
Petroglyphs
Not Used
Not Used
Figurines
Used
Not Yet Used
Formation
Pegmatite rock is holocrystalline, intrusive igneous rock which is formed by partial melting and dewatering during the process of metamorphism.
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.
Mineral Content
Apatite, Beryl, Feldspar, Fluorite, Garnet, Lepidolite, Quartz, Silica, Spodumene, Topaz
Iron Oxides, Pyroxene, Quartz, Stishovite, Sulfides
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, Magnesium Carbonate, MgO, Phosphorus Pentoxide
Carbon Dioxide, Silicon Dioxide, Sulfur Dioxide, Sulphur
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Not Applicable
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Not Applicable
Grain Size
Medium to Coarse Grained
Very fine-grained
Fracture
Conchoidal
Uneven
Streak
White
Light to dark brown
Porosity
Less Porous
Less Porous
Luster
Grainy, Pearly and Vitreous
Vitreous
Cleavage
Perfect
Irregular
Toughness
2.1
Not Available
Specific Gravity
2.6-2.63
2.46-2.86
Transparency
Translucent to Opaque
Transparent to Translucent
Density
2.6-2.65 g/cm3
2.7-2.9 g/cm3
Specific Heat Capacity
Not Available
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant
Heat Resistant
Deposits in Eastern Continents
Asia
China, India, Iran, Japan, Nepal, North Korea, Russia, Saudi Arabia, South Korea
South Korea
Africa
South Africa
Western Africa
Europe
Austria, France, Greece, Ireland, Italy, Netherlands, Slovakia, Spain, Turkey, Ukraine
Great Britain, Switzerland
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
Canada
Not Yet Found
South America
Brazil
Not Yet Found
Deposits in Oceania Continent
Australia
New South Wales, Queensland, South Australia, Western Australia
Central Australia, Western Australia
Pegmatite vs Pseudotachylite Characteristics
Though some rocks look identical, they have certain characteristics which distinguish them from others. Characteristics of rocks include texture, appearance, color, fracture, streak, hardness etc. Pegmatite vs Pseudotachylite characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Pegmatite and Properties of Pseudotachylite. Learn more about Pegmatite vs Pseudotachylite in the next section. The interior uses of Pegmatite include Decorative aggregates, Flooring and Interior decoration whereas the interior uses of Pseudotachylite include Decorative aggregates, Entryways and Interior decoration. Due to some exceptional properties of Pegmatite and Pseudotachylite, they have various applications in construction industry. The uses of Pegmatite in construction industry include As dimension stone, Building houses or walls, Construction aggregate, For road aggregate, Landscaping and that of Pseudotachylite include As dimension stone, Cement manufacture, For road aggregate, Making natural cement.
More about Pegmatite and Pseudotachylite
Here you can know more about Pegmatite and Pseudotachylite. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Pegmatite and Pseudotachylite consists of mineral content and compound content. The mineral content of Pegmatite includes Apatite, Beryl, Feldspar, Fluorite, Garnet, Lepidolite, Quartz, Silica, Spodumene, Topaz and mineral content of Pseudotachylite includes Iron Oxides, Pyroxene, Quartz, Stishovite, Sulfides. You can also check out the list of all Igneous Rocks. When we have to compare Pegmatite vs Pseudotachylite, the texture, color and appearance plays an important role in determining the type of rock. Pegmatite is available in black, brown, cream, green, grey, pink, red, rust, silver, white, yellow colors whereas, Pseudotachylite is available in black, brown, colourless, green, grey, pink, white colors. Appearance of Pegmatite is Layered, Banded, Veined and Shiny and that of Pseudotachylite is Dull and Soft. Properties of rock is another aspect for Pegmatite vs Pseudotachylite. Hardness of Pegmatite and Pseudotachylite is 7. The types of Pegmatite are Granite Pegmatite, Gabbro Pegmatite and Diorite Pegmatite whereas types of Pseudotachylite are Not Available. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Pegmatite is white while that of Pseudotachylite is light to dark brown. The specific heat capacity of Pegmatite is Not Available and that of Pseudotachylite is 0.92 kJ/Kg K. Depending on the properties like hardness, toughness, specific heat capacity, porosity etc., rocks are resistant to heat, wear, impact, etc.Pegmatite is heat resistant, impact resistant, pressure resistant whereas Pseudotachylite is heat resistant.