Scoria is a highly vesicular, dark colored volcanic rock that may or may not contain crystals (phenocrysts). It is typically dark in color (generally dark brown, black or purplish red), and basaltic or andesitic in composition. Scoria is relatively low in density as a result of its numerous macroscopic ellipsoidal vesicles, but in contrast to pumice, all scoria has a specific gravity greater than 1, and sinks in water. The holes or vesicles form when gases that were dissolved in the magma come out of solution as it erupts, creating bubbles in the molten rock, some of which are frozen in place as the rock cools and solidifies. Scoria may form as part of a lava flow, typically near its surface, or as fragmental ejecta (lapilli, blocks and bombs), for instance in Strombolian eruptions that form steep-sided scoria cones. Most scoria is composed of glassy fragments, and may contain phenocrysts. The word scoria comes from the Greek σκωρία, skōria, rust. An old name for scoria is cinder.
For a list of volcanic materials, download the files below:
For a list of volcanic materials, download the files below:
Volcanic Materials by Riza Loreine Comilang.pdf | |
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Volcanic Materials by Francheska Mae Trinidad.pdf | |
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Volcanic Materials by Ma. Elenita Gutierrez.pdf | |
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Wikipedia article Scoria
https://en.wikipedia.org/wiki/Scoria
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Wikipedia article Scoria
https://en.wikipedia.org/wiki/Scoria
See that page's history for attribution.
Text content made available for this website through http://creativecommons.org/licenses/by-sa/3.0/
Next article - - - Sedimentary Rock