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Is Obsidian permeable or impermeable?
Igneous rocks include granite, pumice and obsidian (often called nature’s glass). Some igneous rocks are non-porous and impervious (like granite) because the particles that make it are so tightly packed together.
Is Obsidian non porous?
Porosity of Obsidian It is a less porous rock, so it has a medium hardness.
What igneous rocks are permeable?
The permeability of the rock samples is likely to be – permeable – sandstone, chalk; impermeable – clay, slate, marble, granite.
Which rock is most permeable?
Gravel and sand are both porous and permeable, making them good aquifer materials. Gravel has the highest permeability.
What metamorphic rock can obsidian turn into?
gneiss
Obsidian changes to gneiss under high-grade metamorphic forces.
What type of rock is obsidian?
Obsidian is volcanic glass. The reason it is glassy is because it has no crystal structure. It is classified as an igneous rx, although technically it is not a rock due to the definition of a rx. The reason it is glass and has no crystal structure is due to how fast it is cooled after a volcanic eruption.
What is the difference between pumice and obsidian in composition?
Obsidian with gray layers of rhyolitic pumice in Long Valley Caldera in California. Pumice and rhyolite have very similar composition but they differ in texture — pumice is highly vesicular while obsidian is massive. Is some volcanic glass still basaltic in composition?
What is the difference between volcanic glass and obsidian?
Volcanic glass that formed underwater has alternative names like tachylite and hyaloclastite. Typical obsidian is either black or slightly reddish and often demonstrates beautiful conchoidal fracture. Width of sample 11 cm. So the volcanic glass and obsidian are not synonyms although in many cases you can freely use both terms.
Why does obsidian have a metallic sheen?
Rarely, obsidian has an iridescent or metallic “sheen” caused by light reflecting from minute inclusions of mineral crystals, rock debris, or gas. These colored specimens are known as “rainbow obsidian,” “golden obsidian,” or “silver obsidian,” depending upon the color of the sheen or iridescence.