Definition
Argillites are highly compact sedimentary or slightly metamorphosed rocks that consist largely or wholly of particles of clay or silt but lack the fissility of shale or the cleavage characteristic of slate
Pegmatite rock is a holocrystalline, intrusive igneous rock which is composed of interlocking phaneritic crystals
Discoverer
Unknown
R. J. Hauy
Etymology
From Latin Argilla (clay) and -ite in English which became agrilla+ -ite = Argillite
From Greek pegma, pegmat which means- thing joined together + -ite
Class
Sedimentary Rocks
Igneous Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Hard Rock
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock
Texture
Clastic, Polished
Pegmatitic
Color
Dark Grey to Black, Pink, Red, White
Black, Brown, Cream, Green, Grey, Pink, Red, Rust, Silver, White, Yellow
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Rough and Dull
Layered, Banded, Veined and Shiny
Interior Uses
Decorative Aggregates, Homes, Interior Decoration
Decorative Aggregates, Flooring, Interior Decoration
Exterior Uses
As Building Stone, Garden Decoration, Office Buildings
As Building Stone, As Facing Stone, Paving Stone
Other Architectural Uses
Curbing, Whetstones
Curbing
Construction Industry
Used for flooring, stair treads, borders and window sills.
As Dimension Stone, Building houses or walls, Construction Aggregate, for Road Aggregate, Landscaping
Antiquity Uses
Artifacts, Monuments, Sculpture
Artifacts, Sculpture, Small Figurines
Commercial Uses
Fire resistant, Used to manufracture paperweights and bookends
Creating Artwork, Jewelry, Source of corundum, tourmalines, beryls and topaz
Types
Metamorphic rock
Granite Pegmatite, Gabbro Pegmatite and Diorite Pegmatite
Features
Is one of the oldest rock
Generally rough to touch, Is one of the oldest rock, Source of corundum, tourmalines, beryls and topaz
Archaeological Significance
Formation
An argillite is a fine-grained sedimentary rock mainly composed of clay particles which forms from lithified muds which contain variable amounts of silt-sized particles.
Pegmatite rock is holocrystalline, intrusive igneous rock which is formed by partial melting and dewatering during the process of metamorphism.
Mineral Content
Biotite, Chlorite, Feldspar, Micas, Muscovite or Illite, Plagioclase, Pyrite, Quartz
Apatite, Beryl, Feldspar, Fluorite, Garnet, Lepidolite, Quartz, Silica, Spodumene, Topaz
Compound Content
Iron(III) Oxide, Potassium Oxide, MgO, Silicon Dioxide
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, Magnesium Carbonate, MgO, Phosphorus Pentoxide
Types of Metamorphism
-
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Types of Weathering
Biological Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Grain Size
Fine Grained
Medium to Coarse Grained
Fracture
Conchoidal to Uneven
Conchoidal
Streak
White to Grey
White
Porosity
Highly Porous
Less Porous
Luster
Waxy and Dull
Grainy, Pearly and Vitreous
Specific Gravity
2.56-2.68
2.6-2.63
Transparency
Opaque
Translucent to Opaque
Density
2.54-2.66 g/cm3
2.6-2.65 g/cm3
Resistance
Heat Resistant, Impact Resistant
Heat Resistant, Impact Resistant, Pressure Resistant
Deposits in Eastern Continents
Asia
Bangladesh, China, India, Russia
China, India, Iran, Japan, Nepal, North Korea, Russia, Saudi Arabia, South Korea
Africa
Ethiopia, Kenya, Morocco, South Africa, Tanzania
South Africa
Europe
Austria, France, Germany, Greece, Italy, Romania, Scotland, Spain, Switzerland
Austria, France, Greece, Ireland, Italy, Netherlands, Slovakia, Spain, Turkey, Ukraine
Deposits in Western Continents
South America
Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Brazil
Deposits in Oceania Continent
Australia
New South Wales, New Zealand, Queensland, Victoria, Western Australia
New South Wales, Queensland, South Australia, Western Australia
All about Argillite and Pegmatite Properties
Know all about Argillite and Pegmatite properties here. All properties of rocks are important as they define the type of rock and its application. Argillite belongs to Sedimentary Rocks while Pegmatite belongs to Igneous Rocks.Texture of Argillite is Clastic, Polished whereas that of Pegmatite is Pegmatitic. Argillite appears Rough and Dull and Pegmatite appears Layered, Banded, Veined and Shiny. The luster of Argillite is waxy and dull while that of Pegmatite is grainy, pearly and vitreous. Argillite is available in dark grey to black, pink, red, white colors whereas Pegmatite is available in black, brown, cream, green, grey, pink, red, rust, silver, white, yellow colors. The commercial uses of Argillite are fire resistant, used to manufracture paperweights and bookends and that of Pegmatite are creating artwork, jewelry, source of corundum, tourmalines, beryls and topaz.