Definition
Rhyolite is a fine-grained igneous rock which is rich in silica
Migmatite is typically a granitic rock within a metamorphic host rock which is composed of two intermingled but distinguishable components
Origin
North America
Southern Alps, France
Discoverer
Ferdinand von Richthofen
Jakob Sederholm
Etymology
From German Rhyolit, from Greek rhuax lava stream + lithos stone
From the Greek word migma which means a mixture
Class
Igneous Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Group
Volcanic
Not Applicable
Other Categories
Coarse Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Aphanitic, Glassy, Porphyritic
Foliated
Color
Grey, White, Light Black
Black, Bluish - Grey, Brown, Brown- Black, Dark Greenish - Grey, Dark Grey to Black
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Banded
Dull, Banded and Foilated
Interior Uses
Decorative Aggregates, Homes, Hotels, Interior Decoration, Kitchens
Countertops, Flooring, Kitchens
Exterior Uses
As Building Stone, As Facing Stone, Paving Stone, Office Buildings
As Building Stone, As Facing Stone
Other Architectural Uses
Not Yet Used
Curbing
Construction Industry
Arrowheads, As Dimension Stone, Building houses or walls, Construction Aggregate, Cutting Tool, for Road Aggregate, Knives
As Dimension Stone, Cement Manufacture, for Road Aggregate, Making natural cement
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts
Artifacts
Commercial Uses
Gemstone, Laboratory bench tops, Jewelry
Cemetery Markers, Jewelry, Tombstones, Used to manufracture paperweights and bookends
Types
Pumice Rocks, Obsidian Rocks, Perlite Rocks, Porphyritic Rocks.
Diatexites and Metatexites
Features
Acidic in nature, Available in lots of colors
Generally rough to touch, Is one of the oldest rock
Archaeological Significance
Monuments
Not Yet Used
Not Yet Used
Famous Monuments
Not Applicable
Not Applicable
Sculpture
Not Yet Used
Not Yet Used
Famous Sculptures
Not Applicable
Not Applicable
Pictographs
Not Used
Used
Petroglyphs
Not Used
Used
Figurines
Not Yet Used
Not Yet Used
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.
Migmatites form by high temperature regional and thermal metamorphism of protolith rocks where rocks melt partially due to high temperature.
Mineral Content
Biotite, Feldspar, Hornblade, Plagioclase, Pyroxene, Quartz
Biotite, Chlorite, Feldspar, Garnet, Graphite, Hornblade, Micas, Muscovite or Illite, Quartz, Quartzite, Silica, Zircon
Compound Content
Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide, Sodium
Aluminium Oxide, NaCl, CaO, Carbon Dioxide, Iron(III) Oxide, FeO, Potassium Oxide, Magnesium Carbonate, MgO, MnO, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism
Burial Metamorphism, Cataclastic 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
Chemical Erosion, Glacier Erosion, Water Erosion, Wind Erosion
Grain Size
Large and Coarse Grained
Medium to Fine Coarse Grained
Fracture
Sub-conchoidal
Irregular
Porosity
Highly Porous
Very Less Porous
Luster
Earthy
Dull to Pearly to Subvitreous
Compressive Strength
Not Available
Cleavage
Not Available
Poor
Specific Gravity
2.65-2.67
2.65-2.75
Transparency
Opaque
Opaque
Density
2.4-2.6 g/cm3
Not Available
Resistance
Heat Resistant, Wear Resistant
Heat Resistant, Pressure Resistant
Deposits in Eastern Continents
Asia
China, India
China, India, Iran, Iraq, Kazakhstan, Kyrgyzstan, Mongolia, Russia
Africa
Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa
Cameroon, Ethiopia, Ghana, Kenya, Madagascar, Morocco, Mozambique, Namibia, Nigeria, Tanzania, Togo
Europe
Germany, Iceland, Ireland, Italy, Spain
Albania, Austria, Bosnia and Herzegovina, Finland, France, Georgia, Germany, Hungary, Italy, Kosovo, Monaco, Norway, Poland, Romania, Serbia, Slovakia, Slovenia, Sweden, Switzerland, Ukraine, United Kingdom
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
Canada, USA
Canada, Costa Rica, Cuba, Mexico, Panama, USA
South America
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, Peru, Venezuela
Deposits in Oceania Continent
Australia
New Zealand, Queensland, Western Australia
New South Wales, New Zealand, Queensland, Victoria