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
Theralite is a plutonic hylocrystalline igneous rock consisting of augite, olivine, calcic plagioclase and nepheline
Discoverer
Obsius
Unknown
Etymology
From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius
From Greek to pursue
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Hard Rock
Other Categories
Opaque Rock
Fine Grained Rock, Opaque Rock
Texture
Glassy
Phaneritic
Color
Black, Blue, Brown, Green, Orange, Red, Tan, Yellow
Dark Grey to Black
Durability
Durable
Durable
Scratch Resistant
Yes
Yes
Appearance
Shiny
Veined and Shiny
Interior Uses
Decorative Aggregates, Interior Decoration
Decorative Aggregates, Flooring, Interior Decoration
Exterior Uses
Garden Decoration
As Building Stone, As Facing 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, Cement Manufacture, Construction Aggregate, for Road Aggregate
Medical Industry
Surgery
-
Antiquity Uses
Artifacts, Jewellery
Artifacts, Monuments, Sculpture
Commercial Uses
Creating Artwork, Mirror, Used in aquariums
Cemetery Markers, Commemorative Tablets, Creating Artwork, Laboratory bench tops, Jewelry, Sea Defence, Tombstones
Types
Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian
Teschenite and Essexite
Features
Blocks negativity, Helps to protect against depression
Smooth to touch
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.
Theralite 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
-
Augite, Olivine, Plagioclase, Pyroxene
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Aluminium Oxide, CaO, Chromium(III) Oxide, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Sulfur Trioxide
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Water Erosion, Wind Erosion
Grain Size
-
Fine Grained
Fracture
Conchoidal
Uneven, Splintery or Conchoidal
Porosity
Very Less Porous
Highly Porous
Luster
Vitreous
Waxy and Dull
Specific Gravity
2.6-2.7
2.5-2.8
Transparency
Translucent
Translucent to Opaque
Density
2.6 g/cm3
2.7 g/cm3
Resistance
Heat Resistant, Impact Resistant
Impact Resistant, Pressure Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
Afghanistan, Indonesia, Japan, Russia
India, Russia
Africa
Kenya
South Africa
Europe
Greece, Hungary, Iceland, Italy, Turkey
Germany, Greece, Italy, Scotland, Turkey
Others
-
Greenland, Mid-Atlantic Ridge
Deposits in Western Continents
North America
Canada, Mexico, USA
Canada, USA
South America
Argentina, Chile, Ecuador, Peru
Bolivia, Brazil, Colombia, Venezuela
Deposits in Oceania Continent
Australia
New Zealand
New Zealand, Queensland
Obsidian vs Theralite 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 Theralite characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Obsidian and Properties of Theralite. Learn more about Obsidian vs Theralite in the next section. The interior uses of Obsidian include Decorative aggregates and Interior decoration whereas the interior uses of Theralite include Decorative aggregates, Flooring and Interior decoration. Due to some exceptional properties of Obsidian and Theralite, 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 Theralite include As dimension stone, Building houses or walls, Cement manufacture, Construction aggregate, For road aggregate.
More about Obsidian and Theralite
Here you can know more about Obsidian and Theralite. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Obsidian and Theralite consists of mineral content and compound content. The mineral content of Obsidian includes and mineral content of Theralite includes Augite, Olivine, Plagioclase, Pyroxene. You can also check out the list of all Igneous Rocks. When we have to compare Obsidian vs Theralite, 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, Theralite is available in dark grey to black colors. Appearance of Obsidian is Shiny and that of Theralite is Veined and Shiny. Properties of rock is another aspect for Obsidian vs Theralite. The hardness of Obsidian is 5-5.5 and that of Theralite is 7. The types of Obsidian are Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian whereas types of Theralite are Teschenite and Essexite. Streak of rock is the color of powder produced when it is dragged across an unweathered surface. The streak of Obsidian and Theralite is white. The specific heat capacity of Obsidian is 0.92 kJ/Kg K and that of Theralite is 0.74 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 Theralite is impact resistant, pressure resistant, wear resistant.