Definition
Trachyte is a grey fine-grained volcanic rock which mainly consists of alkali feldspar
Variolites are a group of dark green basic igneous rocks which exhibit pale colored spots, or spherules, especially on weathered surfaces, that give them a pockmarked appearance
Discoverer
Alexandre Brongniart and René Just Haüy
Unknown
Etymology
From Greek trakhus rough’ or trakhutēs roughness
From Latin varius, speckled, variegated
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Other Categories
Fine Grained Rock, Opaque Rock
Opaque Rock
Texture
Aphanitic to Porphyritic
Glassy, Massive, Porphyritic, Scoriaceous, Vesicular
Color
Black, Brown, Dark Greenish - Grey, Green, Grey, Light to Dark Grey, White
Black, Brown, Light to Dark Grey
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Banded
Dull and Soft
Interior Uses
Decorative Aggregates, Flooring, Homes, Interior Decoration
Floor Tiles, Flooring, Homes, Hotels, Kitchens
Exterior Uses
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration, Office Buildings
Garden Decoration, Office Buildings
Other Architectural Uses
Curbing
Curbing
Construction Industry
As Dimension Stone, Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate, Landscaping, Making natural cement, Manufacture of Magnesium and Dolomite Refractories
As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone
Antiquity Uses
Artifacts, Monuments, Sculpture, Small Figurines
Artifacts, Monuments, Sculpture
Commercial Uses
Cemetery Markers, Creating Artwork
Cemetery Markers, Creating Artwork
Types
Felsic volcanic rock
Metamorphic rock
Features
Available in Lots of Colors and Patterns, Is one of the oldest rock, Matrix variable
Has High structural resistance against erosion and climate, Very fine grained rock
Archaeological Significance
Formation
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.
Variolites are a group of dark green basic igneous rocks that exhibit pale colored spots on weathered surfaces that give them a pockmarked appearance.
Mineral Content
Augite, Biotite, Feldspar, Hornblade, Plagioclase, Quartz
Olivine, Plagioclase, Pyroxene
Compound Content
Potassium Oxide, Sodium Oxide, Silicon Dioxide
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Types of Metamorphism
Cataclastic Metamorphism, Contact Metamorphism, Regional 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, Sea Erosion, Water Erosion, Wind Erosion
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Grain Size
Fine Grained
-
Streak
White
White to Grey
Porosity
Less Porous
Less Porous
Specific Gravity
2.7
2.8-3
Transparency
Opaque
Opaque
Density
2.43-2.45 g/cm3
2.9-3.1 g/cm3
Resistance
Heat Resistant, Impact Resistant, Wear Resistant
Heat Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
China, India, Iran, Saudi Arabia, Sri Lanka, Taiwan, Thailand, Turkey, Vietnam
India, Russia
Africa
Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa
South Africa
Europe
Bulgaria, England, Germany, Norway, Romania, Switzerland
Iceland
Deposits in Western Continents
North America
USA
Canada, USA
South America
Brazil, Chile
Brazil
Deposits in Oceania Continent
Australia
New Zealand, Queensland, South Australia, Western Australia
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Trachyte vs Variolite 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. Trachyte vs Variolite characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Trachyte and Properties of Variolite. Learn more about Trachyte vs Variolite in the next section. The interior uses of Trachyte include Decorative aggregates, Flooring, Homes and Interior decoration whereas the interior uses of Variolite include Floor tiles, Flooring, Homes, Hotels and Kitchens. Due to some exceptional properties of Trachyte and Variolite, they have various applications in construction industry. The uses of Trachyte in construction industry include As dimension stone, Building houses or walls, Cement manufacture, Construction aggregate, For road aggregate, Landscaping, Making natural cement, Manufacture of magnesium and dolomite refractories and that of Variolite include As dimension stone, Cobblestones, Rail track ballast, Roadstone.
More about Trachyte and Variolite
Here you can know more about Trachyte and Variolite. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Trachyte and Variolite consists of mineral content and compound content. The mineral content of Trachyte includes Augite, Biotite, Feldspar, Hornblade, Plagioclase, Quartz and mineral content of Variolite includes Olivine, Plagioclase, Pyroxene. You can also check out the list of all Igneous Rocks. When we have to compare Trachyte vs Variolite, the texture, color and appearance plays an important role in determining the type of rock. Trachyte is available in black, brown, dark greenish - grey, green, grey, light to dark grey, white colors whereas, Variolite is available in black, brown, light to dark grey colors. Appearance of Trachyte is Banded and that of Variolite is Dull and Soft. Properties of rock is another aspect for Trachyte vs Variolite. Hardness of Trachyte and Variolite is 6. The types of Trachyte are Felsic volcanic rock whereas types of Variolite are Metamorphic rock. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Trachyte is white while that of Variolite is white to grey. The specific heat capacity of Trachyte is 0.84 kJ/Kg K and that of Variolite is 0.84 kJ/Kg K. Depending on the properties like hardness, toughness, specific heat capacity, porosity etc., rocks are resistant to heat, wear, impact, etc.Trachyte is heat resistant, impact resistant, wear resistant whereas Variolite is heat resistant, pressure resistant, wear resistant.