Definition
Comendite is a hard, peralkaline igneous rock, a type of light blue grey rhyolite
Rhyolite is a fine-grained igneous rock which is rich in silica
Origin
Italy
North America
Discoverer
Unknown
Ferdinand von Richthofen
Etymology
Comendite derives its name from the area of Le Commende on San Pietro Island in Italy
From German Rhyolit, from Greek rhuax lava stream + lithos stone
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Hard Rock
Other Categories
Medium Grained Rock, Opaque Rock
Coarse Grained Rock, Opaque Rock
Texture
Porphyritic
Aphanitic, Glassy, Porphyritic
Color
Blue, Bluish - Grey
Grey, White, Light Black
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Foliated
Banded
Interior Uses
Countertops, Decorative Aggregates, Interior Decoration
Decorative Aggregates, Homes, Hotels, Interior Decoration, Kitchens
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration
As Building Stone, As Facing Stone, Paving Stone, Office Buildings
Other Architectural Uses
Curbing
-
Construction Industry
Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate, Landscaping, Making natural cement, Raw material for the manufacture of mortar
Arrowheads, As Dimension Stone, Building houses or walls, Construction Aggregate, Cutting Tool, for Road Aggregate, Knives
Antiquity Uses
Artifacts
Artifacts
Commercial Uses
Cemetery Markers
Gemstone, Laboratory bench tops, Jewelry
Types
Rhyolite
Pumice Rocks, Obsidian Rocks, Perlite Rocks, Porphyritic Rocks.
Features
Very fine grained rock, It is One of the Oldest, Strongest and Hardest Rock
Acidic in nature, Available in lots of colors
Archaeological Significance
Formation
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.
Rhyolite is a felsic extrusive rock and due to its high silica content, rhyolite lava is very viscous and is volcanic equivalent of granite.
Mineral Content
Albite, Amphibole, Quartz
Biotite, Feldspar, Hornblade, Plagioclase, Pyroxene, Quartz
Compound Content
Al, Fe, Potassium Oxide
Ca, Fe, Potassium Oxide, Mg, Potassium, Silicon Dioxide, Sodium
Types of Metamorphism
Cataclastic Metamorphism, Regional Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Coastal Erosion, Water Erosion
Chemical Erosion, Sea Erosion, Water Erosion, Wind Erosion
Grain Size
Medium Grained
Large and Coarse Grained
Fracture
Pervasive
Sub-conchoidal
Porosity
Highly Porous
Highly Porous
Specific Gravity
2.38
2.65-2.67
Transparency
Opaque
Opaque
Density
-9999 g/cm3
2.4-2.6 g/cm3
Resistance
Heat Resistant, Impact Resistant
Heat Resistant, Wear Resistant
Deposits in Eastern Continents
Africa
East Africa
Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa
Europe
Italy
Germany, Iceland, Ireland, Italy, Spain
Deposits in Western Continents
North America
-
Canada, USA
South America
-
Argentina, Bolivia, Chile, Colombia, Ecuador, Peru, Venezuela
Deposits in Oceania Continent
Australia
Queensland
New Zealand, Queensland, Western Australia