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
Amphibolite can be defined as a granular metamorphic rock which mainly consist of hornblende and plagioclase
Discoverer
Unknown
Alexandre Brongniart
Etymology
From Latin varius, speckled, variegated
From Amphibole + -ite
Class
Igneous Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
Other Categories
Opaque Rock
Coarse Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Glassy, Massive, Porphyritic, Scoriaceous, Vesicular
Banded, Foliated, Massive
Color
Black, Brown, Light to Dark Grey
Black, Brown, Green, Grey
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Dull and Soft
Foliated
Interior Uses
Floor Tiles, Flooring, Homes, Hotels, Kitchens
Countertops, Decorative Aggregates, Entryways, Floor Tiles, Flooring, Homes, Hotels, Kitchens
Exterior Uses
Garden Decoration, Office Buildings
As Building Stone, As Facing Stone, Paving Stone, Office Buildings
Other Architectural Uses
Curbing
Curbing
Construction Industry
As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone
As Dimension Stone, Building houses or walls, Cobblestones, Construction Aggregate, for Road Aggregate, Landscaping, Production of Glass and Ceramics, Roadstone
Antiquity Uses
Artifacts, Monuments, Sculpture
Artifacts, Sculpture, Small Figurines
Commercial Uses
Cemetery Markers, Creating Artwork
Cemetery Markers, Commemorative Tablets, Creating Artwork
Types
Metamorphic rock
Hornblendite
Features
Has High structural resistance against erosion and climate, Very fine grained rock
Clasts are smooth to touch, Matrix variable, Surfaces are often shiny
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.
Amphibolite is a coarse-grained metamorphic rock which forms by metamorphism of mafic igneous rocks like basalt and gabbro or from the metamorphism of clay-rich sedimentary rocks like marl or graywacke.
Mineral Content
Olivine, Plagioclase, Pyroxene
Amphibole, Andalusite, Biotite, Calcite, Epidote, Garnet, Hornblade, Kyanite, Magnetite, Olivine, Plagioclase, Pyroxene, Staurolite, Wollastonite
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
-
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Chemical Weathering, Mechanical Weathering
Types of Erosion
-
Chemical Erosion, Glacier Erosion, Sea Erosion, Wind Erosion
Grain Size
-
Medium to Coarse Grained
Fracture
Conchoidal
Irregular to Conchoidal
Streak
White to Grey
White to Grey
Porosity
Less Porous
Less Porous
Luster
-
Vitreous to Dull
Specific Gravity
2.8-3
2.5
Transparency
Opaque
Opaque
Density
2.9-3.1 g/cm3
2.85-3.07 g/cm3
Resistance
Heat Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
India, Russia
Russia, Turkey
Africa
South Africa
Burundi, Djibouti, Eritrea, Ethiopia, Kenya, Madagascar, Rwanda, Somalia, South Africa, Sudan, Tanzania, Uganda
Europe
Iceland
Germany, Greece, Iceland, Norway, Poland
Deposits in Western Continents
North America
Canada, USA
Canada, USA
South America
Brazil
Brazil
Deposits in Oceania Continent
Australia
-
South Australia, Western Australia
Variolite vs Amphibolite 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. Variolite vs Amphibolite characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Variolite and Properties of Amphibolite. Learn more about Variolite vs Amphibolite in the next section. The interior uses of Variolite include Floor tiles, Flooring, Homes, Hotels and Kitchens whereas the interior uses of Amphibolite include Countertops, Decorative aggregates, Entryways, Floor tiles, Flooring, Homes, Hotels and Kitchens. Due to some exceptional properties of Variolite and Amphibolite, they have various applications in construction industry. The uses of Variolite in construction industry include As dimension stone, Cobblestones, Rail track ballast, Roadstone and that of Amphibolite include As dimension stone, Building houses or walls, Cobblestones, Construction aggregate, For road aggregate, Landscaping, Production of glass and ceramics, Roadstone.
More about Variolite and Amphibolite
Here you can know more about Variolite and Amphibolite. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Variolite and Amphibolite consists of mineral content and compound content. The mineral content of Variolite includes Olivine, Plagioclase, Pyroxene and mineral content of Amphibolite includes Amphibole, Andalusite, Biotite, Calcite, Epidote, Garnet, Hornblade, Kyanite, Magnetite, Olivine, Plagioclase, Pyroxene, Staurolite, Wollastonite. You can also check out the list of all Igneous Rocks. When we have to compare Variolite vs Amphibolite, the texture, color and appearance plays an important role in determining the type of rock. Variolite is available in black, brown, light to dark grey colors whereas, Amphibolite is available in black, brown, green, grey colors. Appearance of Variolite is Dull and Soft and that of Amphibolite is Foliated. Properties of rock is another aspect for Variolite vs Amphibolite. The hardness of Variolite is 6 and that of Amphibolite is 6-7. The types of Variolite are Metamorphic rock whereas types of Amphibolite are Hornblendite. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Variolite and Amphibolite is white to grey. The specific heat capacity of Variolite is 0.84 kJ/Kg K and that of Amphibolite 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.Variolite is heat resistant, pressure resistant, wear resistant whereas Amphibolite is heat resistant, pressure resistant, wear resistant.