Definition
Dacite is a volcanic igneous rock which is rintermediate in composition between andesite and rhyolite
Conglomerate is a sedimentary rock which forms from rounded gravel and boulder sized clasts which are cemented together in a matrix
History
Origin
Romania and Moldova, Europe
Italy
Discoverer
Unknown
Unknown
Etymology
From Dacia, a province of the Roman Empire which lay between the Danube River and Carpathian Mountains where the rock was first described
From Latin conglomeratus, to roll together, i.e. from com together + glomerare to gather into a ball, from glomus (genitive glomeris) a ball
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Soft Rock
Family
Group
Volcanic
-
Other Categories
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock
Texture
Aphanitic to Porphyritic
Clastic
Color
Bluish - Grey, Brown, Grey, Light to Dark Grey
Beige, Black, Brown, Buff, Light to Dark Grey, Orange, Rust, White, Yellow
Maintenance
Less
More
Durability
Durable
Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Vesicular
Shiny and Rounded
Architecture
Interior Uses
Decorative Aggregates, Entryways, Interior Decoration
Decorative Aggregates, Floor Tiles, Homes
Exterior Uses
As Building Stone, Paving Stone, Garden Decoration
As Building Stone, As Facing Stone, Garden Decoration, Office Buildings, Roof Tiles
Other Architectural Uses
Curbing
Curbing
Industry
Construction Industry
As Dimension Stone, Construction Aggregate, for Road Aggregate, Landscaping
As Dimension Stone, Cement Manufacture, Construction Aggregate, for Road Aggregate, Roadstone
Medical Industry
-
-
Antiquity Uses
Artifacts
Artifacts, Monuments, Sculpture, Small Figurines
Other Uses
Commercial Uses
Commemorative Tablets, Creating Artwork
Cemetery Markers, In aquifers, Tombstones
Types
Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite
Orthoconglomerate and Paraconglomerate
Features
Host Rock for Lead, Is one of the oldest rock
Clasts are smooth to touch, Is one of the oldest rock, Matrix variable
Archaeological Significance
Monuments
-
-
Famous Monuments
-
-
Sculpture
-
-
Famous Sculptures
-
-
Pictographs
-
-
Petroglyphs
-
-
Figurines
-
-
Fossils
Absent
Present
Formation
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.
Conglomerate forms where sediments consisting mainly of pebble and cobble-size clasts at least two millimeters in diameter starts accumulating.
Composition
Mineral Content
Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon
Clay, Sand, Silica, Silt
Compound Content
Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide
NaCl, CaO
Transformation
Metamorphism
✔
✘
✔
✘
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism
Weathering
✔
✘
✔
✘
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
-
Erosion
✔
✘
✔
✘
Types of Erosion
Chemical Erosion
Chemical Erosion, Coastal Erosion
Physical Properties
Hardness
2-2.252-3
1
7
👆🏻
Grain Size
Medium to Fine Coarse Grained
Coarse Grained
Fracture
Conchoidal
Uneven
Streak
White
White
Porosity
Less Porous
Highly Porous
Luster
Subvitreous to Dull
Dull
Compressive Strength
70.00 N/mm270.00 N/mm2
0.15
450
👆🏻
Cleavage
Perfect
-
Toughness
-
-
Specific Gravity
2.86-2.872.86-2.88
0
8.4
👆🏻
Transparency
Translucent
Opaque
Density
2.77-2.771 g/cm31.7-2.3 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
0.92 kJ/Kg K0.92 kJ/Kg K
0.14
3.2
👆🏻
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant
Deposits in Eastern Continents
Asia
-
China, India, Kazakhstan, Mongolia, Russia, Uzbekistan
Africa
-
Namibia, Nigeria, South Africa
Europe
France, Greece, Romania, Scotland, Spain
Austria, Denmark, Germany, Great Britain, Netherlands, Norway, Poland, Sweden, Switzerland, United Kingdom
Others
-
Greenland
Deposits in Western Continents
North America
USA
Canada, USA
South America
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Brazil
Deposits in Oceania Continent
Australia
New Zealand, South Australia, Western Australia
New South Wales, New Zealand