Definition
Tachylite is a vitreous form of basaltic volcanic glass. This glass is formed naturally by the rapid cooling of molten basalt
Arkose is a sedimentary rock, specifically a type of sandstone containing at least 25% feldspar
Discoverer
Unknown
Alexandre Brongniart
Etymology
From German Tachylite, from tachy- + Greek lutos soluble, melting
From Auvergne region of France used by a French geologist Alexandre Brongniart in 1826 who applied this term to some feldspathic sandstones
Class
Igneous Rocks
Sedimentary Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Other Categories
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock
Color
Black, Dark Brown
Reddish Brown
Durability
Durable
Durable
Appearance
Glassy
Rough and Dull
Interior Uses
Decorative Aggregates, Interior Decoration
Decorative Aggregates, Homes, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
Paving Stone, Office Buildings
Other Architectural Uses
Curbing
Whetstones
Construction Industry
Cutting Tool, Knives, Landscaping, Scrapers
Cement Manufacture, Construction Aggregate, for Road Aggregate, Production of Glass and Ceramics, Raw material for the manufacture of mortar
Antiquity Uses
Artifacts
Artifacts, Sculpture, Small Figurines
Commercial Uses
Cemetery Markers, Creating Artwork
In aquifers, Soil Conditioner, Source of Magnesia (MgO), Tombstones
Types
Volcanic glass
Arkose
Features
Available in Lots of Colors and Patterns, Clasts are smooth to touch
Available in Lots of Colors and Patterns, Generally rough to touch, Is one of the oldest rock
Archaeological Significance
Formation
Tachylite 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.
Arkose rock forms from the weathering of feldspar-rich igneous or metamorphic rock, most commonly granitic rocks, which are primarily composed of quartz and feldspar.
Mineral Content
Feldspar, Olivine
Calcite, Clay, Clay Minerals, Feldspar, Micas, Quartz
Compound Content
Fe, Mg
Aluminium Oxide, CaO, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
-
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion, Sea Erosion, Water Erosion, Wind Erosion
Coastal Erosion, Glacier Erosion, Water Erosion, Wind Erosion
Grain Size
Medium to Fine Coarse Grained
Coarse Grained
Fracture
Conchoidal
Conchoidal
Porosity
Less Porous
Highly Porous
Transparency
Opaque
Opaque
Density
3.058 g/cm3
-9999 g/cm3
Resistance
Heat Resistant, Impact Resistant, Wear Resistant
Heat Resistant, Impact Resistant, Pressure Resistant
Deposits in Eastern Continents
Asia
Cambodia, Russia, South Korea
China, India, Kazakhstan, Mongolia, Russia, Uzbekistan
Africa
East Africa
Namibia, Nigeria, South Africa
Europe
England, Germany, Hungary, Iceland, Scotland, Sweden
Austria, Denmark, Germany, Great Britain, Netherlands, Norway, Poland, Sweden, Switzerland, United Kingdom
Others
Hawaii Islands
Greenland
Deposits in Western Continents
North America
USA
Canada, USA
Deposits in Oceania Continent
Australia
Victoria
New South Wales, New Zealand