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Magma rich in silica and poor in dissolved water is most easily cooled rapidly enough to form volcanic glass. As a result, rhyolite magmas, which are high in silica, can produce tephra composed entirely of volcanic glass and may also form glassy lava flows. [2] Ash-flow tuffs typically consist of countless microscopic shards of volcanic glass. [3]
Tachylite (/ ˈ t æ k ə l aɪ t / TAK-ə-lyte; also spelled tachylyte) is a form of basaltic volcanic glass. This glass is formed naturally by the rapid cooling of molten basalt. It is a type of mafic igneous rock that is decomposable by acids and readily fusible. [citation needed] The color is a black or dark-brown, and it has a greasy ...
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 ]
Pele's hair, with a hand lens as scale Strands of Pele's hair under microscope view. Pele's hair (closest modern Hawaiian translation: "lauoho o Pele " [1]) is a volcanic glass formation produced from cooled lava stretched into thin strands, usually from lava fountains, lava cascades, or vigorous lava flows.
Pele's tears are also found entangled within fine strands of volcanic glass known as Pele's hair and it was considered that they formed together under similar conditions. [1] Shimozura (1994) investigated this further and found that the velocity of the erupting lava was the main factor in determining whether Pele's tears or Pele's hair were formed.
The study team also chemically analyzed ash and shards of volcanic glass measuring no more than 0.0008 inch (0.02 millimeter) long. ... Volcanic eruptions in 19th century Japan were well ...
The ash is typically made up of microscopic pieces of rock fragments, volcanic glass or a variety of minerals that do not dissolve in water. "Falling ash can turn daylight into complete darkness ...
The other form of vesicles are subspherical to spherical and result from high vapor pressure during an eruption. [11] Reticulite is a type of basaltic pumice formed in very high lava fountains. It has an extremely low density and is composed of a network of volcanic glass formed when the vesicles have almost completely coalesced. [12]