A cinder-like volcanic rock, usually dark brown, red-brown, or black in color.
Solidified fragments of quenched, highly vesicular (>60%) mafic magma or lava (Cashman et al., 2000, p. 421). The highly vesicular nature of scoria results from rapid cooling of gas-rich lava.
Scoria is a vesicular (bubbly) glassy lava rock of basaltic to andesitic composition ejected from a vent during explosive eruption. The bubbly nature of scoria is due to the escape of volcanic gases during eruption. Scoria is typically dark gray to black in color, mostly due to its high iron content. The surface of some scoria may have a blue iridescent color; oxidation may lead to a deep reddish-brown color.
Photograph by J. Lowenstern in September 1990.
Scoria exposed in the cross section of a cinder or scoria cone.
Did you know?
Originally, scoria was the name for the silicate slag left over from the smelting of ore. The word scoria, in fact, stems from the Greek word for refuse or trash. Scoria resembles silicate slag; thus its name.
Because scoria is very hard and porous, it makes a wonderful base for roads (road metal). In volcanic areas, scoria is often quarried from cinder cones and laid out as the foundation for small country roads, or used during winter to provide friction for automobiles.
A highly expanded form of scoria is called reticulite, where bubble walls have burst, leaving a three dimensional network of delicate glass threads. Because reticulite is so expanded, some people call it basaltic pumice.

Glossary of volcanic terms. - University of Wisconsin Oshkosh. . 2001.


Look at other dictionaries:

  • Scoria — is a textural term for macrovesicular volcanic rock. It is commonly, but not exclusively, basaltic or andesitic in composition. Scoria is light as a result of numerous macroscopic ellipsoidal vesicles, but most scoria has a specific gravity… …   Wikipedia

  • scoria — / skorja/ s.f. [dal lat. scoria, gr. skōría, der. di skō̂r escremento ]. 1. (metall.) [spesso al plur., ciò che resta dopo l estrazione o la lavorazione di un metallo e sim.: s. di lavorazione ] ▶◀ (ant.) capomorto, residuo, rifiuto, scarto.… …   Enciclopedia Italiana

  • Scoria — Sco ri*a, n.; pl. {Scori[ae]}. [L., fr. Gr. ?, fr. ? dung, ordure.] 1. The recrement of metals in fusion, or the slag rejected after the reduction of metallic ores; dross. [1913 Webster] 2. Cellular slaggy lava; volcanic cinders. [1913 Webster] …   The Collaborative International Dictionary of English

  • Scorĭa — (gr.), 1) Schlacke; 2) Hautschlacke, der durch die Hautausdünstung abgehende verbrauchte Thierstoff, dessen Zurückballung die sogenannten Scorischen (rheumatischen) Krankheiten erzeugt …   Pierer's Universal-Lexikon

  • scoria — [skôr′ē ə] n. pl. scoriae [skôr′ēē΄] [ME < L < Gr skōria, refuse, dross < skōr, dung: see SCATO ] 1. the slag or refuse left after metal has been smelted from ore 2. loose, cinderlike lava scoriaceous [skôr΄ēā′shəs] adj …   English World dictionary

  • scoria — scoriaceous /skawr ee ay sheuhs, skohr /, adj. /skawr ee euh, skohr /, n., pl. scoriae /skawr ee ee , skohr /. 1. Metall. the refuse, dross, or slag left after melting or smelting metal; scum. 2. Geol. a cinderlike basic cellular lava. [1350… …   Universalium

  • scoria — scò·ria s.f. 1a. TS metall. spec. al pl., residuo solido di un processo di estrazione di un metallo da un minerale che lo contiene 1b. TS metall. spec. al pl., residuo di un processo di rifusione o di affinazione di un metallo o di una lega… …   Dizionario italiano

  • scoria — sco•ri•a [[t]ˈskɔr i ə, ˈskoʊr [/t]] n. pl. sco•ri•ae [[t]ˈskɔr iˌi, ˈskoʊr [/t]] 1) mel the refuse, dross, or slag left after melting or smelting metal 2) gel Geol. a cinderlike basic cellular lava • Etymology: 1350–1400; ME < L scōria <… …   From formal English to slang

  • scoria — noun (plural scoriae) Etymology: Middle English, from Latin, from Greek skōria, from skōr excrement more at scatology Date: 14th century 1. the refuse from melting of metals or reduction of ores ; slag 2. rough vesicular cindery lava •… …   New Collegiate Dictionary

  • scoria — noun /skɔːɹiə/ a) The slag or dross that remains after the smelting of metal from an ore b) A porous rock that is formed by solidified lava, and which can be found around a volcanos crater …   Wiktionary

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