Definition
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
Trachyandesite is an extrusive igneous rock.
Discoverer
Unknown
Unknown
Etymology
From Latin varius, speckled, variegated
From French trachyandésite, trachy + andésite andesite, a lava intermediate in composition between trachyte and andesite
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Other Categories
Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Glassy, Massive, Porphyritic, Scoriaceous, Vesicular
Glassy, Massive, Porphyritic, Scoriaceous, Vesicular
Color
Black, Brown, Light to Dark Grey
Black, Brown, Light to Dark Grey
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Dull and Soft
Dull and Soft
Interior Uses
Floor Tiles, Flooring, Homes, Hotels, Kitchens
Countertops, Decorative Aggregates, Homes, Interior Decoration
Exterior Uses
Garden Decoration, Office Buildings
As Building Stone, As Facing Stone, Garden Decoration
Other Architectural Uses
Curbing
Curbing
Construction Industry
As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone
Building houses or walls, Cobblestones, for Road Aggregate, Rail Track Ballast, Roadstone
Antiquity Uses
Artifacts, Monuments, Sculpture
Artifacts, Sculpture
Commercial Uses
Cemetery Markers, Creating Artwork
Creating Artwork, Pottery
Types
Metamorphic rock
Basaltic Trachyandesite
Features
Has High structural resistance against erosion and climate, Very fine grained rock
Has High structural resistance against erosion and climate, Very fine grained rock
Archaeological Significance
Formation
Variolites are a group of dark green basic igneous rocks that exhibit pale colored spots on weathered surfaces that give them a pockmarked appearance.
Trachyandesite is a fine-grained, hard rock which is a type of metasomatite, essentially altered basalt. It forms with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.
Mineral Content
Olivine, Plagioclase, Pyroxene
Alkali feldspar, Biotite, Olivine, Plagioclase, Pyroxene, Sodic plagioclase
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional 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, Coastal Erosion, Water Erosion, Wind Erosion
Grain Size
-
Fine Grained
Fracture
Conchoidal
Conchoidal
Streak
White to Grey
Light to dark brown
Porosity
Less Porous
Less Porous
Specific Gravity
2.8-3
2.8-3
Transparency
Opaque
Opaque
Density
2.9-3.1 g/cm3
2.9-3.1 g/cm3
Resistance
Heat Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
India, Russia
India, Russia
Africa
South Africa
South Africa
Deposits in Western Continents
North America
Canada, USA
Canada, USA
South America
Brazil
Brazil
Deposits in Oceania Continent
All about Variolite and Trachyandesite Properties
Know all about Variolite and Trachyandesite properties here. All properties of rocks are important as they define the type of rock and its application. Variolite and Trachyandesite belong to Igneous Rocks.Texture of Variolite is Glassy, Massive, Porphyritic, Scoriaceous, Vesicular whereas that of Trachyandesite is Glassy, Massive, Porphyritic, Scoriaceous, Vesicular. Variolite appears Dull and Soft and Trachyandesite appears Dull and Soft. The luster of Variolite is while that of Trachyandesite is earthy. Variolite and Trachyandesite are available in black, brown, light to dark grey colors. The commercial uses of Variolite are cemetery markers, creating artwork and that of Trachyandesite are creating artwork, pottery.