Definition
Mylonite is a metamorphic rock formed by ductile deformation during intense shearing encountered during folding and faulting, a process termed cataclastic or dynamic metamorphism
Skarns are formed during regional or contact metamorphism and from a variety of metasomatic processes involving fluids of magmatic, metamorphic, and/or marine origin
Origin
New Zealand
USA, Australia
Discoverer
Unknown
Tornebohm
Etymology
From Greek mulōn mill + -ite
From an old Swedish mining term originally used to describe a type of silicate gangue or waste rock.
Class
Metamorphic Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Foliated
Earthy, Mud-rich, Rough
Color
Black to Grey
Black, Brown, Green, Grey, White
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Dull, Banded and Foilated
Dull
Interior Uses
Decorative Aggregates, Interior Decoration
Decorative Aggregates, Entryways, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
Other Architectural Uses
Curbing
Curbing
Construction Industry
for Road Aggregate, Landscaping, Roadstone
As a Flux in the Production of Steel and Pig Iron, As a Sintering Agent in Steel Industry to process Iron Ore, As Dimension Stone, Gold and Silver production, Manufacture of Magnesium and Dolomite Refractories
Antiquity Uses
Artifacts, Monuments
Artifacts, Monuments, Sculpture
Commercial Uses
Creating Artwork, Gemstone, Jewelry
Creating Artwork, Gemstone, Jewelry, Metallurgical Flux, Source of Magnesia (MgO)
Types
Blastomylonites, Ultramylonites and Phyllonites
Endoskarns
Features
Surfaces are often shiny
Host Rock for Lead, Zinc and Copper Deposits
Archaeological Significance
Formation
Mylonites are ductilely deformed rocks formed by the accumulation of large shear strain, in ductile fault zones.
Due to change in environmental conditions, rocks are heated and pressurized deep inside the Earth's surface. Skarn is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.
Mineral Content
Porphyroblasts
Calcite, Enstatite, Epidote, Garnet, Magnetite, Pyroxene, Titanite
Compound Content
Aluminium Oxide, Calcium Sulfate, Chromium(III) Oxide, Iron(III) Oxide, Magnesium Carbonate, Silicon Dioxide
Au, CaO, Carbon Dioxide, Cu, Fe, MgO
Types of Metamorphism
-
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
-
Types of Erosion
Chemical Erosion, Sea Erosion, Wind Erosion
-
Grain Size
Fine Grained
Fine Grained
Fracture
Conchoidal
Irregular
Streak
White
Light to dark brown
Porosity
Highly Porous
Less Porous
Luster
Shiny
Waxy and Dull
Cleavage
Conchoidal
Slaty
Specific Gravity
2.97-3.05
2.86
Transparency
Opaque
Opaque
Density
2.6-4.8 g/cm3
2.8-2.9 g/cm3
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant
Heat Resistant
Deposits in Eastern Continents
Asia
China, India, Indonesia, Saudi Arabia, South Korea
China, India, Russia, Saudi Arabia, South Korea, Sri Lanka
Africa
Eritrea, Ethiopia, Ghana, South Africa, Western Africa
South Africa, Western Africa
Europe
England, Finland, France, Germany, Great Britain, Greece, United Kingdom
United Kingdom
Deposits in Western Continents
South America
-
Brazil, Colombia, Paraguay
Deposits in Oceania Continent
Australia
Central Australia, Western Australia
Central Australia, Western Australia
All about Mylonite and Skarn Properties
Know all about Mylonite and Skarn properties here. All properties of rocks are important as they define the type of rock and its application. Mylonite and Skarn belong to Metamorphic Rocks.Texture of Mylonite is Foliated whereas that of Skarn is Earthy, Mud-rich, Rough. Mylonite appears Dull, Banded and Foilated and Skarn appears Dull. The luster of Mylonite is shiny while that of Skarn is waxy and dull. Mylonite is available in black to grey colors whereas Skarn is available in black, brown, green, grey, white colors. The commercial uses of Mylonite are creating artwork, gemstone, jewelry and that of Skarn are creating artwork, gemstone, jewelry, metallurgical flux, source of magnesia (mgo).