Definition
Tachylite is a vitreous form of basaltic volcanic glass. This glass is formed naturally by the rapid cooling of molten basalt
Comendite is a hard, peralkaline igneous rock, a type of light blue grey rhyolite
Discoverer
Unknown
Unknown
Etymology
From German Tachylite, from tachy- + Greek lutos soluble, melting
Comendite derives its name from the area of Le Commende on San Pietro Island in Italy
Class
Igneous Rocks
Igneous 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
Medium Grained Rock, Opaque Rock
Texture
Vitreous
Porphyritic
Color
Black, Dark Brown
Blue, Bluish - Grey
Durability
Durable
Durable
Appearance
Glassy
Foliated
Interior Uses
Decorative Aggregates, Interior Decoration
Countertops, Decorative Aggregates, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
As Building Stone, As Facing Stone, Garden Decoration
Other Architectural Uses
Curbing
Curbing
Construction Industry
Cutting Tool, Knives, Landscaping, Scrapers
Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate, Landscaping, Making natural cement, Raw material for the manufacture of mortar
Antiquity Uses
Artifacts
Artifacts
Commercial Uses
Cemetery Markers, Creating Artwork
Cemetery Markers
Types
Volcanic glass
Rhyolite
Features
Available in Lots of Colors and Patterns, Clasts are smooth to touch
Very fine grained rock, It is One of the Oldest, Strongest and Hardest 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.
Comendite is a type of Igneous rock which is formed due to cooling and solidification of lava or magma. It may form with or without crystallization, either below the surface as intrusive rocks or on the surface as extrusive rocks.
Mineral Content
Feldspar, Olivine
Albite, Amphibole, Quartz
Compound Content
Fe, Mg
Al, Fe, Potassium Oxide
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Cataclastic 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, Water Erosion
Grain Size
Medium to Fine Coarse Grained
Medium Grained
Fracture
Conchoidal
Pervasive
Streak
Vermilion
Bluish Black
Porosity
Less Porous
Highly Porous
Specific Gravity
2.4
2.38
Transparency
Opaque
Opaque
Density
3.058 g/cm3
-9999 g/cm3
Resistance
Heat Resistant, Impact Resistant, Wear Resistant
Heat Resistant, Impact Resistant
Deposits in Eastern Continents
Asia
Cambodia, Russia, South Korea
China
Africa
East Africa
East Africa
Europe
England, Germany, Hungary, Iceland, Scotland, Sweden
Italy
Deposits in Western Continents
Deposits in Oceania Continent
Australia
Victoria
Queensland