Definition
Obsidian is a naturally occurring volcanic glass formed as an extrusive igneous rock. It is produced when felsic lava extruded from a volcano cools rapidly with minimum crystal growth
Hornblendite is a type of igneous plutonic rock consisting mainly of amphibole hornblende and is a type of Amphibolite rock
Discoverer
Obsius
Unknown
Etymology
From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius
From German, Horn horn + blende
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Other Categories
Opaque Rock
Coarse Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Glassy
Banded, Foliated, Massive
Color
Black, Blue, Brown, Green, Orange, Red, Tan, Yellow
Black, Brown, Green, Grey
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Shiny
Foliated
Interior Uses
Decorative Aggregates, Interior Decoration
Countertops, Decorative Aggregates, Entryways, Flooring, Homes, Hotels, Interior Decoration, Kitchens
Exterior Uses
Garden Decoration
As Building Stone, As Facing Stone, Paving Stone, Garden Decoration, Office Buildings
Other Architectural Uses
-
Curbing
Construction Industry
Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points
As Dimension Stone, Building houses or walls, Cobblestones, Construction Aggregate, for Road Aggregate, Landscaping, Production of Glass and Ceramics, Roadstone
Medical Industry
Surgery
-
Antiquity Uses
Artifacts, Jewellery
Artifacts, Sculpture, Small Figurines
Commercial Uses
Creating Artwork, Mirror, Used in aquariums
Cemetery Markers, Commemorative Tablets, Creating Artwork
Types
Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian
Hornblende Gabbro and Hornblende Peridotite
Features
Blocks negativity, Helps to protect against depression
Clasts are smooth to touch, Matrix variable, Surfaces are often shiny
Archaeological Significance
Formation
When the lava is released from volcano, it undergoes a very rapid cooling which freezes the mechanisms of crystallization. The result is a volcanic glass with a uniform smooth texture.
Hornblendite 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.
Mineral Content
-
Amphibole, Calcite, Hornblade, Magnetite, Plagioclase, Wollastonite
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
-
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Chemical Erosion, Water Erosion, Wind Erosion
Grain Size
-
Medium to Coarse Grained
Fracture
Conchoidal
Irregular to Conchoidal
Streak
White
White to Grey
Porosity
Very Less Porous
Less Porous
Luster
Vitreous
Vitreous to Dull
Specific Gravity
2.6-2.7
2.5
Transparency
Translucent
Opaque
Density
2.6 g/cm3
2.85-3.07 g/cm3
Resistance
Heat Resistant, Impact Resistant
Heat Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
Afghanistan, Indonesia, Japan, Russia
Russia, Turkey
Africa
Kenya
Burundi, Djibouti, Eritrea, Ethiopia, Kenya, Madagascar, Rwanda, Somalia, South Africa, Sudan, Tanzania, Uganda
Europe
Greece, Hungary, Iceland, Italy, Turkey
Germany, Greece, Iceland, Norway, Poland
Deposits in Western Continents
North America
Canada, Mexico, USA
Canada, USA
South America
Argentina, Chile, Ecuador, Peru
Brazil
Deposits in Oceania Continent
Australia
New Zealand
South Australia, Western Australia
Obsidian vs Hornblendite Characteristics
Though some rocks look identical, they have certain characteristics which distinguish them from others. Characteristics of rocks include texture, appearance, color, fracture, streak, hardness etc. Obsidian vs Hornblendite characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Obsidian and Properties of Hornblendite. Learn more about Obsidian vs Hornblendite in the next section. The interior uses of Obsidian include Decorative aggregates and Interior decoration whereas the interior uses of Hornblendite include Countertops, Decorative aggregates, Entryways, Flooring, Homes, Hotels, Interior decoration and Kitchens. Due to some exceptional properties of Obsidian and Hornblendite, they have various applications in construction industry. The uses of Obsidian in construction industry include Arrowheads, Cutting tool, Knives, Scrapers, Spear points and that of Hornblendite include As dimension stone, Building houses or walls, Cobblestones, Construction aggregate, For road aggregate, Landscaping, Production of glass and ceramics, Roadstone.
More about Obsidian and Hornblendite
Here you can know more about Obsidian and Hornblendite. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Obsidian and Hornblendite consists of mineral content and compound content. The mineral content of Obsidian includes and mineral content of Hornblendite includes Amphibole, Calcite, Hornblade, Magnetite, Plagioclase, Wollastonite. You can also check out the list of all Igneous Rocks. When we have to compare Obsidian vs Hornblendite, the texture, color and appearance plays an important role in determining the type of rock. Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors whereas, Hornblendite is available in black, brown, green, grey colors. Appearance of Obsidian is Shiny and that of Hornblendite is Foliated. Properties of rock is another aspect for Obsidian vs Hornblendite. The hardness of Obsidian is 5-5.5 and that of Hornblendite is 6-7. The types of Obsidian are Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian whereas types of Hornblendite are Hornblende Gabbro and Hornblende Peridotite. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Obsidian is white while that of Hornblendite is white to grey. The specific heat capacity of Obsidian is 0.92 kJ/Kg K and that of Hornblendite is 0.84 kJ/Kg K. Depending on the properties like hardness, toughness, specific heat capacity, porosity etc., rocks are resistant to heat, wear, impact, etc.Obsidian is heat resistant, impact resistant whereas Hornblendite is heat resistant, pressure resistant, wear resistant.