GeoWord of the Day

The GeoWord of the Day is a free service of the American Geosciences Institute. All of the terms and definitions are from the Glossary of Geology, 5th Edition Revised.

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balas ruby (bal'-as). A pale rose-red or orange gem variety of spinel, found in Badakhshan (or Balascia) province in northern Afghanistan. See also: ruby spinel. Syn: ballas.

Giggenbach bottle . An evacuated alkaline-solution-filled bottle (e.g., sodium hydroxide, NaOH), generally connected to a titanium or silica tube which is inserted into a fumarole. The gases bubble through the solution, condense, and are absorbed by the solution, which can be analyzed (William-Jones and Rymer, 2000).

statospore (stat'-o-spore). A resting spore, e.g. a siliceous thick-walled resistant cyst formed within the frustules of various chiefly marine centric diatoms, and characterized by two overlapping convex valves and by absence of a girdle; or an intracellular cyst in various algae of the division Chrysophyta.

slieve . An Irish term for a mountain.

quasicratonic (qua''-si-cra-ton'-ic). Said of semiconsolidated regions in which paratectonic deformation ( germanotype tectonics ) tends to dominate (Stille, 1940). Obsolete. Syn: semicratonic.

assay (as'-say). v. In economic geology, to analyze the proportions of metals in an ore; to test an ore or mineral for composition, purity, weight, or other properties of commercial interest. n. The test or analysis itself; its results.

arsenowaylandite . An ill-defined arsenic analogue of waylandite: (Bi3+,Sr)(Al,Fe)3(AsO4,PO4)2(OH)6. A member of the crandallite group. Not approved by the International Mineralogical Association.

remnant arc . A fossil volcanic arc commonly in the back-arc position of an active arc.

creaseyite (crea'-sey-ite). A pale green or yellowish orthorhombic mineral: Pb2Cu2Fe3+2Si5O17•6H2O .

wool . An English term for a sandy shale or shaly flagstone with irregular curly bands or bedding.


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