Definition
Rhyodacite is an extrusive volcanic rock intermediate in composition between dacite and rhyolite
Lignite is a soft brownish coal which shows traces of plants and is intermediate between bituminous coal and peat
Discoverer
Unknown
Unknown
Etymology
Rhyo lite + dacite : a rock intermediate between rhyolite and dacite that is the extrusive equivalent of granodiorite
From French, Latin lignum wood + -ite1
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Soft Rock
Group
Volcanic
Not Applicable
Other Categories
Fine Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Earthy
Amorphous, Glassy
Color
Black to Grey, Dark Greenish - Grey
Black, Brown, Dark Brown, Grey, Light to Dark Grey
Durability
Durable
Durable
Appearance
Skeletal
Veined or Pebbled
Interior Uses
Decorative Aggregates, Interior Decoration
Not Yet Used
Exterior Uses
As Building Stone, Garden Decoration
Not Yet Used
Other Architectural Uses
Curbing
Not Yet Used
Construction Industry
As Dimension Stone, Construction Aggregate, for Road Aggregate, Landscaping
for Road Aggregate, Steel Production
Medical Industry
Not Yet Used
Not Yet Used
Antiquity Uses
Artifacts
Not Yet Used
Commercial Uses
Cemetery Markers, Creating Artwork
Electricity Generation
Types
Not Available
Xyloid Lignite or Fossil Wood and Compact Lignite or Perfect Lignite
Features
Available in Lots of Colors and Patterns
Generally rough to touch, Helps in production of Heat and Electricity, Used as fossil fuel
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
Figurines
Not Yet Used
Not Yet Used
Formation
Rhyodacite 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.
Coal formation takes place due to accumulation of plant debris in a swamp environment. The Coal formation process continues, as peat turns into lignite brown or black coal at increasing heat and pressure.
Mineral Content
Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon
Not Available
Compound Content
Ca, Fe, Potassium Oxide, NA, Potassium, Silicon Dioxide
Carbon, Hydrogen, Nitrogen, Oxygen, Sulphur
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Not Applicable
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Chemical Erosion, Water Erosion, Wind Erosion
Grain Size
Fine Grained
Medium to Fine Coarse Grained
Fracture
Conchoidal
Conchoidal
Porosity
Less Porous
Highly Porous
Luster
Greasy to Dull
Dull to Vitreous to Submetallic
Compressive Strength
Not Available
Cleavage
Not Available
Non-Existent
Toughness
2.1
Not Available
Specific Gravity
2.34-2.40
1.1-1.4
Transparency
Opaque
Opaque
Density
Not Available
800-801 g/cm3
Resistance
Heat Resistant
Heat Resistant
Deposits in Eastern Continents
Asia
China, India, Iran, Saudi Arabia, Sri Lanka, Taiwan, Thailand, Turkey, Vietnam
Bangladesh, Burma, Cambodia, China, India, Indonesia, Kazakhstan, Malaysia, Mongolia, Pakistan, Turkey, Vietnam
Africa
Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa
Botswana, Kenya, Morocco, Mozambique, South Africa, Tanzania
Europe
Austria, Belgium, Finland, France, Germany, Italy, Norway, Sardinia, Spain, Switzerland
Belgium, Bulgaria, England, France, Germany, Greece, Hungary, Kosovo, Netherlands, Norway, Poland, Romania, Serbia, Slovakia, Slovenia, The Czech Republic, Ukraine, United Kingdom
Others
Not Yet Found
Not Yet Found
Deposits in Western Continents
North America
Canada, USA
Canada, Mexico, USA
South America
Not Yet Found
Brazil, Chile, Colombia, Venezuela
Deposits in Oceania Continent
Australia
Not Yet Found
New South Wales, Queensland, Victoria