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
Trachyte is a grey fine-grained volcanic rock which mainly consists of alkali feldspar
Discoverer
Unknown
Alexandre Brongniart and René Just Haüy
Etymology
From Greek mulōn mill + -ite
From Greek trakhus rough’ or trakhutēs roughness
Class
Metamorphic Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Medium Hardness Rock
Other Categories
Fine Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Foliated
Aphanitic to Porphyritic
Color
Black to Grey
Black, Brown, Dark Greenish - Grey, Green, Grey, Light to Dark Grey, White
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Dull, Banded and Foilated
Banded
Interior Uses
Decorative Aggregates, Interior Decoration
Decorative Aggregates, Flooring, Homes, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration, Office Buildings
Other Architectural Uses
Curbing
Curbing
Construction Industry
for Road Aggregate, Landscaping, Roadstone
As Dimension Stone, Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate, Landscaping, Making natural cement, Manufacture of Magnesium and Dolomite Refractories
Antiquity Uses
Artifacts, Monuments
Artifacts, Monuments, Sculpture, Small Figurines
Commercial Uses
Creating Artwork, Gemstone, Jewelry
Cemetery Markers, Creating Artwork
Types
Blastomylonites, Ultramylonites and Phyllonites
Felsic volcanic rock
Features
Surfaces are often shiny
Available in Lots of Colors and Patterns, Is one of the oldest rock, Matrix variable
Archaeological Significance
Formation
Mylonites are ductilely deformed rocks formed by the accumulation of large shear strain, in ductile fault zones.
Trachyte is an igneous volcanic rock with an aphanitic to porphyritic texture. It is the volcanic equivalent of syenite rock and forms as a result of magmatic differentiation.
Mineral Content
Porphyroblasts
Augite, Biotite, Feldspar, Hornblade, Plagioclase, Quartz
Compound Content
Aluminium Oxide, Calcium Sulfate, Chromium(III) Oxide, Iron(III) Oxide, Magnesium Carbonate, Silicon Dioxide
Potassium Oxide, Sodium Oxide, Silicon Dioxide
Types of Metamorphism
-
Cataclastic Metamorphism, Contact Metamorphism, Regional Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion, Sea Erosion, Wind Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Sea Erosion, Water Erosion, Wind Erosion
Grain Size
Fine Grained
Fine Grained
Porosity
Highly Porous
Less Porous
Specific Gravity
2.97-3.05
2.7
Transparency
Opaque
Opaque
Density
2.6-4.8 g/cm3
2.43-2.45 g/cm3
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant
Heat Resistant, Impact Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
China, India, Indonesia, Saudi Arabia, South Korea
China, India, Iran, Saudi Arabia, Sri Lanka, Taiwan, Thailand, Turkey, Vietnam
Africa
Eritrea, Ethiopia, Ghana, South Africa, Western Africa
Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa
Europe
England, Finland, France, Germany, Great Britain, Greece, United Kingdom
Bulgaria, England, Germany, Norway, Romania, Switzerland
Deposits in Western Continents
South America
-
Brazil, Chile
Deposits in Oceania Continent
Australia
Central Australia, Western Australia
New Zealand, Queensland, South Australia, Western Australia