WebObsidian ( / əbˈsɪdi.ən, ɒb -/) [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] Obsidian is produced from felsic lava, rich in the lighter elements such as silicon, oxygen, aluminium, sodium, and potassium. WebPumice (/ ˈ p ʌ m ɪ s /), called pumicite in its powdered or dust form, is a volcanic rock that consists of highly vesicular rough-textured volcanic glass, which may or may not contain crystals.It is typically light-colored. Scoria …
Obsidian: Igneous Rock - Pictures, Uses, Properties
WebStudy with Quizlet and memorize flashcards containing terms like Which of the following is true about rocks? a. Rocks are composed of only one mineral. b. Rocks do not contain any non-mineral matter. c. Coal is not considered a true rock. d. Most rocks are a mixture of minerals., What is a naturally occurring, solid mass of mineral or mineral-like matter? a. a … WebA dark, volcanic glass formed by the very rapid solidification of lava. Today's crossword puzzle clue is a general knowledge one: A dark, volcanic glass formed by the very rapid … fm global holdings
What is the structure of obsidian? - Quora
WebMay 3, 2009 · Obsidian, a volcanic glass, sometimes results from extremely rapid cooling of lava. Slower cooling lava will result in crystal formation, albeit small crystal formation, resulting in an... WebPortions of this obsidian flow are mixed with layers of pumice, a glassy, bubble-rich, lightweight rock that develops when water vapor (steam) escapes rapidly from the molten glass at or near the ground surface. Sometimes obsidian of excellent quality develops as surface lava flows. WebLava will sometimes cool so quickly that not even microscopic crystals will form in it. As a result, volcanic glass will form with a shiny, smooth appearance that reflects light. This texture is called glassy . Just like the mineral quartz , a glassy rock will have conchoidal fracture with distinctive, rounded fracture edges. fm global hot work procedure