Definition
Rhyolite is a fine-grained igneous rock which is rich in silica
Epidosite is a highly altered epidote and quartz bearing rock which is a type of metasomatite, essentially altered basalt
Discoverer
Ferdinand von Richthofen
Unknown
Etymology
From German Rhyolit, from Greek rhuax lava stream + lithos stone
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Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Other Categories
Coarse Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained 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
Decorative Aggregates, Floor Tiles, Homes, Hotels, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Paving Stone, Office Buildings
As Facing Stone, Garden Decoration, Office Buildings, Paving Stone
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, Small Figurines
Commercial Uses
Gemstone, Laboratory bench tops, Jewelry
Commemorative Tablets, Creating Artwork
Types
Pumice Rocks, Obsidian Rocks, Perlite Rocks, Porphyritic Rocks.
Alkaline Basalt, Boninite, High Alumina Basalt, Mid Ocean Ridge Basalt (MORB), Tholeiitic Basalt, Basaltic trachyandesite, Mugearite and Shoshonite
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.
Epidosite 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
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, Hydrothermal Metamorphism, Impact 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
Fine to 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
-9999 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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