1,449,764
edits
(Updated rock class item discussion page with longer source data descriptions) |
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Igneous rock in which the framework of the rock consists of crystals that are too small to determine mineralogy with the unaided eye. | Igneous rock in which the framework of the rock consists of crystals that are too small to determine mineralogy with the unaided eye. | ||
= Geoscience Ontology Description = | = Geoscience Ontology Description = | ||
Igneous rock in which the framework of the rock consists of crystals that are too small to determine mineralogy with the unaided eye; framework may include up to 50 percent glass. A significant percentage of the rock by volume may be phenocrysts. Includes rocks that are generally called volcanic rocks. | |||
Need to make decision as to whether devitrified glass should be considered glass or microcrystalline framework for purposes of categorization | Need to make decision as to whether devitrified glass should be considered glass or microcrystalline framework for purposes of categorization | ||