Definition
Dacite is a volcanic igneous rock which is rintermediate in composition between andesite and rhyolite
Claystone is a fine-grained, dark gray to pink sedimentary rock which mainly consists of compacted and hardened clay
Origin
Romania and Moldova, Europe
-
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 English clay and stone as the rock contains more amount of clay
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Soft Rock
Durable Rock, Medium Hardness Rock
Other Categories
Fine Grained Rock, Medium Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Aphanitic to Porphyritic
Clastic
Color
Bluish - Grey, Brown, Grey, Light to Dark Grey
Black, Blue, Brown, Green, Grey, Orange, Red, White, Yellow
Durability
Durable
Durable
Appearance
Vesicular
Rough and Dull
Interior Uses
Decorative Aggregates, Entryways, Interior Decoration
Decorative Aggregates, Entryways, Floor Tiles, Homes, Interior Decoration
Exterior Uses
As Building Stone, Paving Stone, Garden Decoration
As Facing Stone, Roof Tiles
Other Architectural Uses
Curbing
Curbing
Construction Industry
As Dimension Stone, Construction Aggregate, for Road Aggregate, Landscaping
As a Sintering Agent in Steel Industry to process Iron Ore, Cement Manufacture, Construction Aggregate, for Road Aggregate, Making natural cement, Raw material for the manufacture of mortar
Antiquity Uses
Artifacts
Artifacts, Sculpture, Small Figurines
Commercial Uses
Commemorative Tablets, Creating Artwork
Pottery
Types
Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite
Claystone
Features
Host Rock for Lead, Is one of the oldest rock
Available in Lots of Colors and Patterns, Smooth to touch, Very fine grained rock
Archaeological Significance
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.
Claystone is generally quite soft, but can be hard and brittle. It forms due to weathering of mudstone.
Mineral Content
Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon
Biotite, Chlorite, Feldspar, Micas, Muscovite or Illite, Plagioclase, Pyrite, Quartz
Compound Content
Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide
Aluminium Oxide, Ca, NaCl, CaO, Iron(III) Oxide, MgO, Silicon Dioxide
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism
-
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion
Coastal Erosion, Water Erosion
Grain Size
Medium to Fine Coarse Grained
Fine Grained
Porosity
Less Porous
Very Less Porous
Luster
Subvitreous to Dull
Dull
Specific Gravity
2.86-2.87
0
Transparency
Translucent
Opaque
Density
2.77-2.771 g/cm3
2-2.9 g/cm3
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Impact Resistant
Deposits in Eastern Continents
Asia
-
Bangladesh, China, India, Russia
Africa
-
Ethiopia, Kenya, Morocco, South Africa, Tanzania
Europe
France, Greece, Romania, Scotland, Spain
Austria, France, Germany, Greece, Italy, Romania, Scotland, Spain, Switzerland
Deposits in Western Continents
North America
USA
Canada, Panama, USA
South America
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Deposits in Oceania Continent
Australia
New Zealand, South Australia, Western Australia
New South Wales, New Zealand, Queensland, Victoria, Western Australia