Obsidian (/ ə b ˈ s ɪ d i. ən, ɒ b-/ əb-SID-ee-ən ob-) [5] is a naturally occurring volcanic glass formed when lava extruded from a volcano cools rapidly with minimal crystal growth. It is an igneous rock. [6] Produced from felsic lava, obsidian is rich in the lighter elements such as silicon, oxygen, aluminium, sodium, and potassium.

Nov 8, 2023 · Obsidian is an extrusive igneous rock. It is occurring as a natural glass formed by the rapid cooling of viscous lava from volcanoes. Result of this formed, glass occupies more than 80 % and that have seeming conchoidal fracture and vitreous luster. It usually colours dark, black, grey-black to grey.

Obsidian is an igneous rock that forms when molten rock material cools so rapidly that atoms are unable to arrange themselves into a crystalline structure. It is an amorphous material known as a "mineraloid." The result is a volcanic glass with a smooth uniform texture that breaks with a conchoidal fracture (see photo). Where Does Obsidian Form?

Dec 6, 2024 · obsidian, igneous rock occurring as a natural glass formed by the rapid cooling of viscous lava from volcanoes. Obsidian is extremely rich in silica (about 65 to 80 percent), is low in water , and has a chemical composition similar to rhyolite .

Jun 23, 2023 · How is obsidian formed, and where? Obsidian forms from rapid quenching by water or air of highly viscous, silica-rich rhyolitic magma low in volatiles on or near the Earth’s surface. However, it can also form as an intrusive rock on the edges of dikes, rhyolitic flows, plugs, necks, lenses, or sills.

Obsidian typically forms near the end of a volcanic cycle and is often associated with domes of volcanic rock, such as the hills of Glass Buttes, Oregon. If obsidian is similar in composition to granite and rhyolite, both of which were originally molten, then why is obsidian glassy?

Jul 14, 2024 · How does obsidian form? Obsidian forms from the quick quenching of silica-rich, highly viscous rhyolitic magma or lava. The rapid quenching and high viscosity (polymerized magma) hinder nucleation and crystal growth, forming an amorphous glass.

Obsidian is a naturally occurring volcanic glass formed when molten lava from a volcano cools rapidly with minimal crystal growth. It is an igneous rock , meaning it forms from the cooling and solidification of magma or lava.

Jan 11, 2024 · Obsidian is a naturally occurring volcanic glass and one of the most striking types of igneous rocks. This article delves into what obsidian is, its formation and composition, the different...

For obsidian to form, magma is trapped below the eutectic, point of crystallization, by loss of heat. Therefore leaving a magma that is unable to crystallize will form (glass) obsidian.