Definition
Tachylite is a vitreous form of basaltic volcanic glass. This glass is formed naturally by the rapid cooling of molten basalt
Eclogite is an extreme metamorphic rock, formed by regional metamorphism of basalt rock under very high pressure and temperature
Discoverer
Unknown
René Just Haüy
Etymology
From German Tachylite, from tachy- + Greek lutos soluble, melting
From French, Greek eklogē selection with reference to the selective content of the rock + -ite1
Class
Igneous Rocks
Metamorphic Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Medium Hardness Rock
Other Categories
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Fine Grained Rock, Opaque Rock
Color
Black, Dark Brown
Black, Brown, Green, Grey, Pink, White
Durability
Durable
Durable
Appearance
Glassy
Dull, Banded and Foilated
Interior Uses
Decorative Aggregates, Interior Decoration
Decorative Aggregates, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
Paving Stone, Garden Decoration
Other Architectural Uses
Curbing
Curbing
Construction Industry
Cutting Tool, Knives, Landscaping, Scrapers
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Medical Industry
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In Chemical and Pharmaceutical Industry, Medicines and Cosmetics
Antiquity Uses
Artifacts
Artifacts
Commercial Uses
Cemetery Markers, Creating Artwork
Creating Artwork, Gemstone
Types
Volcanic glass
Eclogite
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.
Eclogite forms from high-pressure metamorphism of mafic igneous rocks mainly, basalt or gabbro as it plunges into the mantle in a subduction zone.
Mineral Content
Feldspar, Olivine
Amphibole, Coesite, Corundum, Dolomite, Garnet, Kyanite, Lawsonite, Paragonite, Phengite, Pyroxene, Quartz, Rutile, Zoisite
Compound Content
Fe, Mg
Aluminium Oxide, NaCl, CaO, Carbon Dioxide, Iron(III) Oxide, Magnesium Carbonate, MgO, Sodium Oxide, Potassium, Sodium
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
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Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Mechanical Weathering
Types of Erosion
Chemical Erosion, Sea Erosion, Water Erosion, Wind Erosion
Chemical Erosion, Sea Erosion
Grain Size
Medium to Fine Coarse Grained
Fine Grained
Porosity
Less Porous
Less Porous
Luster
Resinous
Subvitreous to Dull
Specific Gravity
2.4
2.86-2.87
Transparency
Opaque
Opaque
Density
3.058 g/cm3
3.2-3.6 g/cm3
Resistance
Heat Resistant, Impact Resistant, Wear Resistant
Heat Resistant
Deposits in Eastern Continents
Asia
Cambodia, Russia, South Korea
India, Kazakhstan, Kuwait, Russia, South Korea, Thailand, Turkey
Africa
East Africa
Ethiopia, Morocco, South Africa
Europe
England, Germany, Hungary, Iceland, Scotland, Sweden
France, Germany, Italy, Norway, Scotland
Others
Hawaii Islands
Greenland
Deposits in Western Continents
North America
USA
Canada, Costa Rica, Panama, USA
South America
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Argentina, Brazil, Colombia, Ecuador
Deposits in Oceania Continent
Australia
Victoria
Central Australia, New Zealand, Queensland