Definition
Rhyolite is a fine-grained igneous rock which is rich in silica
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
Origin
North America
France
Discoverer
Ferdinand von Richthofen
Unknown
Etymology
From German Rhyolit, from Greek rhuax lava stream + lithos stone
From Latin varius, speckled, variegated
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
Other Categories
Coarse Grained Rock, Opaque Rock
Opaque Rock
Texture
Aphanitic, Glassy, Porphyritic
Glassy, Massive, Porphyritic, Scoriaceous, Vesicular
Color
Grey, White, Light Black
Black, Brown, Light to Dark Grey
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Banded
Dull and Soft
Interior Uses
Decorative Aggregates, Homes, Hotels, Interior Decoration, Kitchens
Floor Tiles, Flooring, Homes, Hotels, Kitchens
Exterior Uses
As Building Stone, As Facing Stone, Paving Stone, Office Buildings
Garden Decoration, Office Buildings
Other Architectural Uses
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Curbing
Construction Industry
Arrowheads, As Dimension Stone, Building houses or walls, Construction Aggregate, Cutting Tool, for Road Aggregate, Knives
As Dimension Stone, Cobblestones, Rail Track Ballast, Roadstone
Antiquity Uses
Artifacts
Artifacts, Monuments, Sculpture
Commercial Uses
Gemstone, Laboratory bench tops, Jewelry
Cemetery Markers, Creating Artwork
Types
Pumice Rocks, Obsidian Rocks, Perlite Rocks, Porphyritic Rocks.
Metamorphic rock
Features
Acidic in nature, Available in lots of colors
Has High structural resistance against erosion and climate, Very fine grained rock
Archaeological Significance
Formation
Rhyolite is a felsic extrusive rock and due to its high silica content, rhyolite lava is very viscous and is volcanic equivalent of granite.
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
Biotite, Feldspar, Hornblade, Plagioclase, Pyroxene, Quartz
Olivine, Plagioclase, Pyroxene
Compound Content
Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide, Sodium
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, 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, Sea Erosion, Water Erosion, Wind Erosion
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Grain Size
Large and Coarse Grained
-
Fracture
Sub-conchoidal
Conchoidal
Porosity
Highly Porous
Less Porous
Specific Gravity
2.65-2.67
2.8-3
Transparency
Opaque
Opaque
Density
2.4-2.6 g/cm3
2.9-3.1 g/cm3
Resistance
Heat Resistant, Wear Resistant
Heat Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
China, India
India, Russia
Africa
Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa
South Africa
Europe
Germany, Iceland, Ireland, Italy, Spain
Iceland
Deposits in Western Continents
North America
Canada, USA
Canada, USA
South America
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Brazil
Deposits in Oceania Continent
Australia
New Zealand, Queensland, Western Australia
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Rhyolite 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. Rhyolite vs Variolite characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Rhyolite and Properties of Variolite. Learn more about Rhyolite vs Variolite in the next section. The interior uses of Rhyolite include Decorative aggregates, Homes, Hotels, Interior decoration and Kitchens whereas the interior uses of Variolite include Floor tiles, Flooring, Homes, Hotels and Kitchens. Due to some exceptional properties of Rhyolite and Variolite, they have various applications in construction industry. The uses of Rhyolite in construction industry include Arrowheads, As dimension stone, Building houses or walls, Construction aggregate, Cutting tool, For road aggregate, Knives and that of Variolite include As dimension stone, Cobblestones, Rail track ballast, Roadstone.
More about Rhyolite and Variolite
Here you can know more about Rhyolite and Variolite. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Rhyolite and Variolite consists of mineral content and compound content. The mineral content of Rhyolite includes Biotite, Feldspar, Hornblade, Plagioclase, Pyroxene, 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 Rhyolite vs Variolite, the texture, color and appearance plays an important role in determining the type of rock. Rhyolite is available in grey, white, light black colors whereas, Variolite is available in black, brown, light to dark grey colors. Appearance of Rhyolite is Banded and that of Variolite is Dull and Soft. Properties of rock is another aspect for Rhyolite vs Variolite. The hardness of Rhyolite is 6-7 and that of Variolite is 6. The types of Rhyolite are Pumice Rocks, Obsidian Rocks, Perlite Rocks, Porphyritic Rocks. 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 Rhyolite is while that of Variolite is white to grey. The specific heat capacity of Rhyolite is 0.71 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.Rhyolite is heat resistant, wear resistant whereas Variolite is heat resistant, pressure resistant, wear resistant.