Definition
Websterite is ultramafic and ultrabasic rock that consists of roughly equal proportions of orthopyroxene and clinopyroxene. It is a special type of pyroxenite.
Tachylite is a vitreous form of basaltic volcanic glass. This glass is formed naturally by the rapid cooling of molten basalt
History
Origin
Webster, North Carolina
Iceland
Discoverer
Unknown
Unknown
Etymology
From the town of Webster located in North Carolina
From German Tachylite, from tachy- + Greek lutos soluble, melting
Class
Igneous Rocks
Igneous Rocks
Sub-Class
Durable Rock, Hard Rock
Durable Rock, Medium Hardness Rock
Family
Group
Plutonic
Volcanic
Other Categories
Coarse Grained Rock, Opaque Rock
Coarse Grained Rock, Fine Grained Rock, Medium Grained Rock, Opaque Rock
Texture
Clastic, Granular, Phaneritic, Porphyritic
Vitreous
Color
Black to Grey, Bluish - Grey, Dark Greenish - Grey, Green, Light Greenish Grey
Black, Dark Brown
Maintenance
Less
More
Durability
Durable
Durable
Water Resistant
✔
✘
✔
✘
Scratch Resistant
✔
✘
✔
✘
Stain Resistant
✔
✘
✔
✘
Wind Resistant
✔
✘
✔
✘
Acid Resistant
✔
✘
✔
✘
Appearance
Layered, Banded, Veined and Shiny
Glassy
Architecture
Interior Uses
Countertops, Decorative Aggregates, Entryways, Floor Tiles, Flooring, Interior Decoration
Decorative Aggregates, Interior Decoration
Exterior Uses
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
As Building Stone, As Facing Stone, Garden Decoration, Paving Stone
Other Architectural Uses
Curbing
Curbing
Industry
Construction Industry
As Dimension Stone, Building houses or walls, Cement Manufacture, Construction Aggregate, for Road Aggregate
Cutting Tool, Knives, Landscaping, Scrapers
Medical Industry
-
-
Antiquity Uses
Artifacts
Artifacts
Other Uses
Commercial Uses
Cemetery Markers, Commemorative Tablets, Creating Artwork, Laboratory bench tops, Jewelry, Sea Defence, Tombstones
Cemetery Markers, Creating Artwork
Types
Ultramafic rock
Volcanic glass
Features
Generally rough to touch, Is one of the oldest rock
Available in Lots of Colors and Patterns, Clasts are smooth to touch
Archaeological Significance
Monuments
-
-
Famous Monuments
-
-
Sculpture
-
-
Famous Sculptures
-
-
Pictographs
-
-
Petroglyphs
-
-
Figurines
-
-
Fossils
Absent
Absent
Formation
Websterite can be formed as cumulates in ultramafic intrusions by accumulation of pyroxene crystals at the base of the lava chamber.
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.
Composition
Mineral Content
Amphibole, Augite, Bronzite, Chromite, Diopside, Enstatite, Garnet, Hornblende, Hypersthene, Magnetite, Pyroxene
Feldspar, Olivine
Compound Content
Aluminium Oxide, CaO, Chromium(III) Oxide, Iron(III) Oxide, Potassium Oxide, MgO, Sodium Oxide, Silicon Dioxide, Sulfur Trioxide
Fe, Mg
Transformation
Metamorphism
✔
✘
✔
✘
Types of Metamorphism
Burial Metamorphism, Impact Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
Weathering
✔
✘
✔
✘
Types of Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Biological Weathering, Chemical Weathering, Mechanical Weathering
Erosion
✔
✘
✔
✘
Types of Erosion
Chemical Erosion, Coastal Erosion, Glacier Erosion, Water Erosion, Wind Erosion
Chemical Erosion, Sea Erosion, Water Erosion, Wind Erosion
Physical Properties
Hardness
75.5
1
7
👆🏻
Grain Size
Coarse Grained
Medium to Fine Coarse Grained
Fracture
Uneven
Conchoidal
Streak
White, Greenish White or Grey
Vermilion
Porosity
Less Porous
Less Porous
Luster
Dull to Vitreous to Submetallic
Resinous
Compressive Strength
95.00 N/mm2206.00 N/mm2
0.15
450
👆🏻
Cleavage
-
-
Toughness
-
-
Specific Gravity
3.2-3.52.4
0
8.4
👆🏻
Transparency
Opaque
Opaque
Density
3.1-3.6 g/cm33.058 g/cm3
0
1400
👆🏻
Thermal Properties
Specific Heat Capacity
0.79 kJ/Kg K0.56 kJ/Kg K
0.14
3.2
👆🏻
Resistance
Impact Resistant, Pressure Resistant, Wear Resistant
Heat Resistant, Impact Resistant, Wear Resistant
Deposits in Eastern Continents
Asia
India, Russia
Cambodia, Russia, South Korea
Africa
South Africa
East Africa
Europe
Germany, Greece, Italy, Scotland, Turkey
England, Germany, Hungary, Iceland, Scotland, Sweden
Others
Greenland
Hawaii Islands
Deposits in Western Continents
North America
Canada, USA
USA
South America
Brazil, Colombia, Venezuela
-
Deposits in Oceania Continent
Australia
New Zealand, Queensland
Victoria