Definition
Rhyolite is a fine-grained igneous rock which is rich in silica
Granodiorite is a coarse-grained intrusive igneous rock containing quartz and plagioclase, and which has composition in between granite and diorite
History
Origin
North America
-
Discoverer
Ferdinand von Richthofen
Unknown
Etymology
From German Rhyolit, from Greek rhuax lava stream + lithos stone
From granite + diorite
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Family
Group
Volcanic
Plutonic
Other Categories
Coarse Grained Rock, Opaque Rock
Coarse Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Aphanitic, Glassy, Porphyritic
Granular, Phaneritic
Color
Grey, White, Light Black
Black, Grey, Orange, Pink, White
Maintenance
More
More
Durability
Durable
Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Banded
Veined or Pebbled
Architecture
Interior Uses
Decorative Aggregates, Homes, Hotels, Interior Decoration, Kitchens
Bathrooms, Countertops, Decorative Aggregates, Entryways, Floor Tiles, Flooring, Homes, Hotels, Interior Decoration, Stair Treads
Exterior Uses
As Building Stone, As Facing Stone, Paving Stone, Office Buildings
As Building Stone, Bridges, Paving Stone, Garden Decoration, Office Buildings, Resorts
Other Architectural Uses
-
-
Industry
Construction Industry
Arrowheads, As Dimension Stone, Building houses or walls, Construction Aggregate, Cutting Tool, for Road Aggregate, Knives
As Dimension Stone
Medical Industry
-
-
Antiquity Uses
Artifacts
Artifacts, Monuments, Sculpture
Other Uses
Commercial Uses
Gemstone, Laboratory bench tops, Jewelry
Curling, Gemstone, Laboratory bench tops, Tombstones
Types
Pumice Rocks, Obsidian Rocks, Perlite Rocks, Porphyritic Rocks.
Granodiorite
Features
Acidic in nature, Available in lots of colors
Available in Lots of Colors and Patterns
Archaeological Significance
Monuments
-
-
Famous Monuments
-
-
Sculpture
-
-
Famous Sculptures
-
-
Pictographs
-
-
Petroglyphs
-
-
Figurines
-
-
Fossils
Absent
Absent
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.
Granodiorite is an intrusive igneous rock which is very hard, crystalline and is visibly homogeneous in texture and forms by melting of continental rocks.
Composition
Mineral Content
Biotite, Feldspar, Hornblade, Plagioclase, Pyroxene, Quartz
Amphibole, Biotite, Feldspar, Hornblade, Micas, Muscovite or Illite, Plagioclase, Pyroxene, Quartz
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
Transformation
Metamorphism
✔
✘
✔
✘
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Weathering
✔
✘
✔
✘
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Chemical Weathering
Erosion
✔
✘
✔
✘
Types of Erosion
Chemical Erosion, Sea Erosion, Water Erosion, Wind Erosion
Chemical Erosion, Glacier Erosion, Wind Erosion
Physical Properties
Hardness
6-76
1
7
👆🏻
Grain Size
Large and Coarse Grained
Medium to Coarse Grained
Fracture
Sub-conchoidal
-
Streak
-
White
Porosity
Highly Porous
Less Porous
Luster
Earthy
Grainy, Pearly and Vitreous
Compressive Strength
140.00 N/mm2175.00 N/mm2
0.15
450
👆🏻
Cleavage
-
-
Toughness
2
-
Specific Gravity
2.65-2.672.6-2.7
0
8.4
👆🏻
Transparency
Opaque
Opaque
Density
2.4-2.6 g/cm32.6-2.8 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
0.71 kJ/Kg K0.79 kJ/Kg K
0.14
3.2
👆🏻
Resistance
Heat Resistant, Wear Resistant
Heat Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
China, India
China, India, Iran, Saudi Arabia, Sri Lanka, Taiwan, Thailand, Turkey, Vietnam
Africa
Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa
Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa
Europe
Germany, Iceland, Ireland, Italy, Spain
Austria, Belgium, Finland, France, Germany, Italy, Norway, Sardinia, Spain, Switzerland, The Czech Republic
Others
-
-
Deposits in Western Continents
North America
Canada, USA
Canada, USA
South America
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
-
Deposits in Oceania Continent
Australia
New Zealand, Queensland, Western Australia
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