Definition
Felsite is a very fine grained volcanic rock that may or may not contain larger crystals and light colored rock that typically requires petrographic examination or chemical analysis for more precise definition
  
Dacite is a volcanic igneous rock which is rintermediate in composition between andesite and rhyolite
  
History
  
  
Origin
Unknown
  
Romania and Moldova, Europe
  
Discoverer
Unknown
  
Unknown
  
Etymology
From English feldspar and -ite
  
From Dacia, a province of the Roman Empire which lay between the Danube River and Carpathian Mountains where the rock was first described
  
Class
Igneous Rocks
  
Igneous Rocks
  
Sub-Class
Durable Rock, Medium Hardness Rock
  
Durable Rock, Soft Rock
  
Family
  
  
Group
Volcanic
  
Volcanic
  
Other Categories
Fine Grained Rock, Opaque Rock
  
Fine Grained Rock, Medium Grained Rock, Opaque Rock
  
Texture
Arborescent Patterned, Vitreous
  
Aphanitic to Porphyritic
  
Color
Black, Blue, Brown, Green, Orange, Red, Tan, Yellow
  
Bluish - Grey, Brown, Grey, Light to Dark Grey
  
Maintenance
Less
  
Less
  
Durability
Durable
  
Durable
  
Water Resistant
Yes
  
No
  
Scratch Resistant
Yes
  
No
  
Stain Resistant
No
  
No
  
Wind Resistant
Yes
  
No
  
Acid Resistant
No
  
No
  
Appearance
Layered, Banded, Veined and Shiny
  
Vesicular
  
Architecture
  
  
Interior Uses
Decorative Aggregates, Flooring, Interior Decoration
  
Decorative Aggregates, Entryways, Interior Decoration
  
Exterior Uses
Paving Stone, Garden Decoration
  
As Building Stone, Paving Stone, Garden Decoration
  
Other Architectural Uses
Curbing
  
Curbing
  
Industry
  
  
Construction Industry
Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points
  
As Dimension Stone, Construction Aggregate, for Road Aggregate, Landscaping
  
Medical Industry
Surgery
  
Not Yet Used
  
Antiquity Uses
Artifacts
  
Artifacts
  
Other Uses
  
  
Commercial Uses
Mirror, Jewelry
  
Commemorative Tablets, Creating Artwork
  
Types
Not Available
  
Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite
  
Features
Available in Lots of Colors and Patterns, Clasts are smooth to touch, Splintery, Very fine grained rock
  
Host Rock for Lead, 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
Used
  
Used
  
Petroglyphs
Used
  
Used
  
Figurines
Not Yet Used
  
Not Yet Used
  
Fossils
Absent
  
Absent
  
Formation
Felsite 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.
  
Dacitic magma is formed by the subduction of young oceanic crust under a thick felsic continental plate. Further, the Oceanic crust is hydrothermally altered as quartz and sodium are added.
  
Composition
  
  
Mineral Content
Feldspar, Iron Oxides
  
Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon
  
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
  
Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide
  
Transformation
  
  
Metamorphism
Yes
  
Yes
  
Types of Metamorphism
Burial Metamorphism, Contact Metamorphism, Impact Metamorphism, Regional Metamorphism
  
Burial Metamorphism, Cataclastic Metamorphism
  
Weathering
Yes
  
Yes
  
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
  
Biological Weathering, Chemical Weathering, Mechanical Weathering
  
Erosion
Yes
  
Yes
  
Types of Erosion
Chemical Erosion, Glacier Erosion, Water Erosion
  
Chemical Erosion
  
Physical Properties
  
  
Hardness
5-5.5
  
2-2.25
  
Grain Size
Fine Grained
  
Medium to Fine Coarse Grained
  
Fracture
Conchoidal
  
Conchoidal
  
Streak
White
  
White
  
Porosity
Very Less Porous
  
Less Porous
  
Luster
Vitreous
  
Subvitreous to Dull
  
Compressive Strength
Not Available
  
Cleavage
Non-Existent
  
Perfect
  
Toughness
Not Available
  
Not Available
  
Specific Gravity
2.6-2.7
  
2.86-2.87
  
Transparency
Translucent
  
Translucent
  
Density
2.6 g/cm3
  
2.77-2.771 g/cm3
  
Thermal Properties
  
  
Specific Heat Capacity
0.92 kJ/Kg K
  
10
0.92 kJ/Kg K
  
10
Resistance
Heat Resistant, Impact Resistant
  
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
  
Deposits in Eastern Continents
  
  
Asia
Afghanistan, Indonesia, Japan, Russia
  
Not Yet Found
  
Africa
Kenya
  
Not Yet Found
  
Europe
Greece, Hungary, Iceland, Italy, Turkey
  
France, Greece, Romania, Scotland, Spain
  
Others
Not Yet Found
  
Not Yet Found
  
Deposits in Western Continents
  
  
North America
Canada, Mexico, USA
  
USA
  
South America
Argentina, Chile, Ecuador, Peru
  
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
  
Deposits in Oceania Continent
  
  
Australia
New Zealand
  
New Zealand, South Australia, Western Australia