Definition
Dacite is a volcanic igneous rock which is rintermediate in composition between andesite and rhyolite
Diatomite is a fine-grained sedimentary rock which is formed from consolidated diatomaceous earth
History
Origin
Romania and Moldova, Europe
Germany
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 diatom + -ite1
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
Fine Grained Rock, Opaque Rock
Texture
Aphanitic to Porphyritic
Clastic or Non-Clastic
Color
Bluish - Grey, Brown, Grey, Light to Dark Grey
Grey, White, Yellow
Maintenance
Less
Less
Durability
Durable
Non-Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Vesicular
Soft
Architecture
Interior Uses
Decorative Aggregates, Entryways, Interior Decoration
Decorative Aggregates, Homes, Interior Decoration
Exterior Uses
As Building Stone, Paving Stone, Garden Decoration
Garden Decoration, Paving Stone
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, Landscaping, Making natural cement, Source of calcium
Medical Industry
-
-
Antiquity Uses
Artifacts
Artifacts
Other Uses
Commercial Uses
Commemorative Tablets, Creating Artwork
Alumina Refineries, Animal feed filler, As a Feed Additive for Livestock, Creating Artwork, Drawing on blackboards, Fire resistant, Gymnasts, athletes and mountain climbers use for grip, In aquifers, Soil Conditioner, To ignite fire, Used as a filter medium, Used as an insecticide, Whiting material in toothpaste, paint and paper
Types
Footwall Dacite, Hanging wall Dacite, Tuff and Biotite Dacite
Diatomite
Features
Host Rock for Lead, Is one of the oldest rock
Clasts are smooth to touch, Is one of the oldest rock, Smooth to touch, Very fine grained rock
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.
Diatomite rock formed from the skeletal remains of single celled plants called diatoms. When diatoms die, their skeletal remains sink to the bottom of lakes and oceans etc. hence forming diatomite deposit.
Composition
Mineral Content
Amphibole, Apatite, Biotite, Feldspar, Garnet, Hornblade, Magnetite, Plagioclase, Pyroxene, Quartz, Zircon
Calcite, Clay, Clay Minerals, Quartz, Sand
Compound Content
Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide
Ca, NaCl, CaO
Transformation
Metamorphism
✔
✘
✔
✘
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism
-
Weathering
✔
✘
✔
✘
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Erosion
✔
✘
✔
✘
Types of Erosion
Chemical Erosion
Chemical Erosion, Coastal Erosion, Wind Erosion
Physical Properties
Hardness
2-2.251
1
7
👆🏻
Grain Size
Medium to Fine Coarse Grained
Very fine-grained
Fracture
Conchoidal
-
Streak
White
White
Porosity
Less Porous
Highly Porous
Luster
Subvitreous to Dull
Dull
Compressive Strength
70.00 N/mm2-
0.15
450
👆🏻
Cleavage
Perfect
-
Toughness
-
1
Specific Gravity
2.86-2.872.3-2.4
0
8.4
👆🏻
Transparency
Translucent
Opaque
Density
2.77-2.771 g/cm32.49-2.51 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
0.92 kJ/Kg K0.90 kJ/Kg K
0.14
3.2
👆🏻
Resistance
Heat Resistant, Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant
Deposits in Eastern Continents
Asia
-
Brunei, India, Indonesia, Malaysia, Singapore, Thailand, Vietnam
Africa
-
Cameroon, Chad, Ghana, Kenya, Malawi, Sudan, Tanzania, Togo, Zambia, Zimbabwe
Europe
France, Greece, Romania, Scotland, Spain
England, France, Germany, Spain, United Kingdom
Others
-
-
Deposits in Western Continents
North America
USA
Canada, USA
South America
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Colombia
Deposits in Oceania Continent
Australia
New Zealand, South Australia, Western Australia
Adelaide, New Zealand, Queensland, Victoria, Yorke Peninsula