Match each rock specimen in Column I with its primary mode of geological formation and major economic importance described in Column II.
- ObsidianGlassy extrusive igneous rock formed by extremely rapid lava cooling, used historically for surgical blades and ornamental carvings.
- GypsumEvaporite sedimentary rock composed of calcium sulfate, widely mined for manufacturing plaster of Paris and drywall.
- SchistFoliated metamorphic rock characterized by aligned mica crystals, formed through regional metamorphism of shale.
- AnthraciteMetamorphosed high-grade coal formed under intense heat and tectonic pressure, valued as a hard, clean-burning fuel.
Answer
Obsidian matches with the glassy extrusive igneous rock used for surgical tools and ornaments; Gypsum matches with the evaporite sedimentary rock used for plaster of Paris; Schist matches with the foliated metamorphic rock derived from shale; and Anthracite matches with the metamorphosed high-grade coal valued as a clean-burning fuel.
Obsidian is a volcanic glass produced by extremely rapid cooling of lava. Gypsum forms chemically via evaporite precipitation in saline bodies of water and is mined for plaster production. Schist is produced through regional metamorphism of shale, characterized by coarse platy mica foliation. Anthracite forms when intense pressure and heat metamorphose coal into a high-density, low-smoke fuel source.
Step-by-Step Solution
Key Concept
Genetic classification, structural characteristics, and economic utility of igneous, sedimentary, and metamorphic rocks.
Estimated Time:1m 30s