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Gabbro identification and geology
A dark-colored, coarse-grained phaneritic mafic intrusive igneous rock composed primarily of calcium-rich plagioclase feldspar and pyroxene augite , with or without olivine. Gabbro is the intrusive equivalent of basalt and forms the lower portion of the oceanic crust. It has a silica content of approximately 45–52% and a specific gravity of about 3.0. Field: petrology. Example: The Bushveld Complex in South Africa contains a massive layered gabbro intrusion that hosts the world's largest reserves of platinum group elements, chromium, and vanadium.. Related terms: Basalt, Mafic, Diorite, Oceanic crust.
Sources, scope & corrections
These authoritative resources support category-level nomenclature, terminology, identification methods, and safety. When a specimen-specific safety warning appears, the public-health source listed here directly supports that precaution. They are not line-by-line citations for every other property on this entry, and natural specimens vary.
- Editorial owner
- GeoMiner
- Last updated
- 2026-03-30T15:19:41.999576+00:00
- Review status
- Published; not independently peer-reviewed
- USGS Thesaurus — U.S. Geological Survey. Controlled earth-science terminology used to describe USGS information resources.
- Glossary of Geologic Terms — U.S. National Park Service. Geologic definitions prepared by the NPS Geologic Resources Inventory.
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