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
Tachylite is a vitreous form of basaltic volcanic glass. This glass is formed naturally by the rapid cooling of molten basalt
Discoverer
Obsius
Unknown
Etymology
From Latin obsidianus, misprint of Obsianus (lapis) (stone) of Obsius
From German Tachylite, from tachy- + Greek lutos soluble, melting
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Medium Hardness Rock
Durable Rock, Medium Hardness Rock
Other Categories
Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Color
Black, Blue, Brown, Green, Orange, Red, Tan, Yellow
Black, Dark Brown
Durability
Durable
Durable
Interior Uses
Decorative Aggregates, Interior Decoration
Decorative Aggregates, Interior Decoration
Exterior Uses
Garden Decoration
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
Other Architectural Uses
-
Curbing
Construction Industry
Arrowheads, Cutting Tool, Knives, Scrapers, Spear Points
Cutting Tool, Knives, Landscaping, Scrapers
Medical Industry
Surgery
-
Antiquity Uses
Artifacts, Jewellery
Artifacts
Commercial Uses
Creating Artwork, Mirror, Used in aquariums
Cemetery Markers, Creating Artwork
Types
Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian
Volcanic glass
Features
Blocks negativity, Helps to protect against depression
Available in Lots of Colors and Patterns, Clasts are 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.
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.
Mineral Content
-
Feldspar, Olivine
Compound Content
Aluminium Oxide, CaO, Iron(III) Oxide, FeO, Potassium Oxide, MgO, MnO, Sodium Oxide, Phosphorus Pentoxide, Silicon Dioxide, Titanium Dioxide
Fe, Mg
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional 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, Sea Erosion, Water Erosion, Wind Erosion
Grain Size
-
Medium to Fine Coarse Grained
Fracture
Conchoidal
Conchoidal
Porosity
Very Less Porous
Less Porous
Specific Gravity
2.6-2.7
2.4
Transparency
Translucent
Opaque
Density
2.6 g/cm3
3.058 g/cm3
Resistance
Heat Resistant, Impact Resistant
Heat Resistant, Impact Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
Afghanistan, Indonesia, Japan, Russia
Cambodia, Russia, South Korea
Europe
Greece, Hungary, Iceland, Italy, Turkey
England, Germany, Hungary, Iceland, Scotland, Sweden
Deposits in Western Continents
North America
Canada, Mexico, USA
USA
South America
Argentina, Chile, Ecuador, Peru
-
Deposits in Oceania Continent
Australia
New Zealand
Victoria
Obsidian vs Tachylite 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 Tachylite characteristics assist us to distinguish and recognize rocks. Also you can check about Properties of Obsidian and Properties of Tachylite. Learn more about Obsidian vs Tachylite in the next section. The interior uses of Obsidian include Decorative aggregates and Interior decoration whereas the interior uses of Tachylite include Decorative aggregates and Interior decoration. Due to some exceptional properties of Obsidian and Tachylite, 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 Tachylite include Cutting tool, Knives, Landscaping, Scrapers.
More about Obsidian and Tachylite
Here you can know more about Obsidian and Tachylite. The life cycle of a rock consists of formation of rock, composition of rock and transformation of rock. The composition of Obsidian and Tachylite consists of mineral content and compound content. The mineral content of Obsidian includes and mineral content of Tachylite includes Feldspar, Olivine. You can also check out the list of all Igneous Rocks. When we have to compare Obsidian vs Tachylite, 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, Tachylite is available in black, dark brown colors. Appearance of Obsidian is Shiny and that of Tachylite is Glassy. Properties of rock is another aspect for Obsidian vs Tachylite. The hardness of Obsidian is 5-5.5 and that of Tachylite is 5.5. The types of Obsidian are Fireworks Obsidian, Mahogany, Sheen Obsidian, Snowflake obsidian and Velvet Peacock Obsidian whereas types of Tachylite are Volcanic glass. 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 Tachylite is vermilion. The specific heat capacity of Obsidian is 0.92 kJ/Kg K and that of Tachylite is 0.56 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 Tachylite is heat resistant, impact resistant, wear resistant.