It is a usually black or banded, hard volcanic glass that displays shiny, curved surfaces when fractured and is formed by very rapid cooling of lava.
The curved fracture surfaces are more correctly termed conchoidal fractures and the "glass" is said to have a "vitreous" texture as the material cools so rapidly that crystals do not have time to form.
Obsidian is formed from the extreme rapid cooling of lava. The rock has been named 'volcanic glass' as it is very smooth and is also translucent. The rock is igneous as it is formed from lava.
A usally black mor banded hard volcanic glass that display shiny ,curved surfaces when fracture and rapid cooling lava bye Victoriasometimesright
obsidian is ''volcanic glass''. It happens when water and lava touch, the chemical compound is
70--75% SiO2,
plus MgO, Fe3O4
Felsic lava.
Igneous rocks are formed from cooling lava. Some examples are obsidian And basalt.
One type of glassy igneous rock is obsidian, which is black and glass-like. Any type of igneous rock that is glassy would be a extrusive rock, which means it was formed outside the earths crust and cooled quickly, making for a fine grain and small crystals. hope this helps
These are all formed by volcanic activity. Igneous
obsidian obsidian
obsidian
Obsidian is black glass formed by volcanoes.
Obsidian and coal are both rocks and they are formed by lava
Obsidian is formed from very rapidly cooling lava.
Igneous rocks
Volcanic rocks like obsidian is formed when lava undergoes very rapid cooling.
Obsidian and Pāhoehoe lava
Obsidian
Igneous rocks are formed from cooling lava. Some examples are obsidian And basalt.
An igneous rock is formed when magma cools and hardens. Some examples of igneous rocks are pumice and obsidian.
Obsidian is a type of volcanic glass formed from quickly cooled lava, so it does not have layers of banding like sedimentary rocks. Instead, obsidian typically has a smooth, uniform texture with occasional swirls or flow lines caused by the rapid cooling process.
Granite is a rock, whereas obsidian is a type of glass formed by cooling lava.
Igneous Rocks are formed. Obsidian is a volcanic glass, go to wikepidiea and search "list of rocks" and it will come up with all the different igneous, metamorphic, and sedimentary rocks and what they are.