Gabbro
A rock classification type
This page is currently not sponsored. Click here to sponsor this page.
About Gabbro
A gabbroid composed of 10-90% Ca-dominant plagioclase and >5% clinopyroxene.
A group of basic intrusive igneous rocks composed principally of basic plagioclase (commonly labradorite or bytownite) and clinopyroxene (augite), with or without olivine and orthopyroxene; also, any member of that group. It is the approximate coarse-grained/intrusive equivalent of basalt. Apatite, magnetite, and ilmenite are common accessory minerals. Commonly dark-colored.
A group of basic intrusive igneous rocks composed principally of basic plagioclase (commonly labradorite or bytownite) and clinopyroxene (augite), with or without olivine and orthopyroxene; also, any member of that group. It is the approximate coarse-grained/intrusive equivalent of basalt. Apatite, magnetite, and ilmenite are common accessory minerals. Commonly dark-colored.
Unique Identifiers
Mindat ID:
48275
Long-form identifier:
mindat:1:1:48275:0
Similar Names
| Gabbro (s.s.) | A synonym of 'Clinopyroxene-gabbro' |
Classification of Gabbro

Gabbro is in section 10 of the QAPF diagram.
Sub-divisions of Gabbro
- Gabbro
- Allalin-gabbro
- Cumulitic gabbro
- Orbicular gabbro
- Clinopyroxene-gabbro
- Olivine-gabbro
- Gabbronorite
- Olivine-gabbronorite
- Pyroxene-hornblende-gabbronorite
- Hornblende-gabbro
- Norite
- Clinopyroxene-norite
- Olivine-clinopyroxene norite
- Olivine-norite
- Pyroxene-hornblende-norite
- Olivine-orthopyroxene-gabbro
- Orthopyroxene-gabbro
- Pyroxene-hornblende-gabbro
- Troctolite
- Gabbrodiorite
- Leucogabbro
- Melagabbro
- Quartz-norite
- Microgabbro
- Pegmatitic gabbro
- Quartz gabbro
- Anorthitissite
- Ferrogabbro
Mineralogy of Gabbro
Essential minerals - these are minerals that are required within the classification of this rock:
| Feldspar > Plagioclase | (Na,Ca)[(Si,Al)AlSi2]O8 |
| Mafic minerals | A petrological term for dark, rock-forming minerals rich in magnesium and/or iron. |
Non-essential minerals - these minerals are common, sometimes major components, but are not always present:
| Amphibole > Hornblende | AnCa2(Z2+5-mZ3+m)(Si8-(n+m)Al(n+m))(OH,F,Cl)2 |
| Mica > Biotite | K(Fe2+/Mg)2(Al/Fe3+/Mg/Ti)([Si/Al/Fe]2Si2O10)(OH/F)2 |
Age distribution
Recorded ages:
Neochaotian to Quaternary : ~4600 Ma to 0 Ma - based on 23 recorded ages.
Sample ages:
| Sample ID | Recorded age | Geologic Time | Dating method |
|---|---|---|---|
| 1 | 12.8 ± 1.3 Ma | Miocene | K-Ar |
| 2 | 16 ± 1 Ma | Miocene | K-Ar |
| 3 | 43 ± 2 Ma | Eocene | K-Ar |
| 4 | 53.1 ± 4.2 to 44 ± 2 Ma | Eocene | K-Ar for the gabbro |
| 5 | 90 ± 2 Ma | Late/Upper Cretaceous | K-Ar |
| 6 | 92.5 ± 3 to 83 ± 3 Ma | Late/Upper Cretaceous | K-Ar |
| 7 | 125 Ma | Early/Lower Cretaceous | K-Ar |
| 8 | 130 to 124 Ma | Early/Lower Cretaceous | K-Ar |
| 9 | 136 ± 4 to 110 ± 9 Ma | Early/Lower Cretaceous | K-Ar |
| 10 | 140 ± 3 to 135 ± 3 Ma | Early/Lower Cretaceous | K-Ar |
| 11 | 229 ± 5 Ma | Late/Upper Triassic | K-Ar |
| 12 | 258.8 ± 2.3 Ma | Lopingian | U-Pb zircon from gabbro |
| 13 | 261 ± 2 Ma | Guadalupian | U-Pb |
| 14 | 305.9 ± 3.5 Ma | Pennsylvanian | Re-Os |
| 15 | 419.2 ± 3.2 to 358.9 ± 0.4 Ma | Devonian | |
| 16 | 2701 ± 8 Ma | Neoarchean | Sm-Nd |
| 17 | ~4600 to 541 ± 1.0 Ma | Precambrian |
Sample references:
Chemical Analysis
Oxide wt%:
| 1 | 2 | 3 | |
|---|---|---|---|
| SiO2 | 46.8 % | 43.18 % | 34.14 % |
| Al2O3 | 15.3 % | 15.85 % | 13.4 % |
| Fe2O3 | 12.5 % | 2.00 % | 2.00 % |
| MnO | 0.14 % | 0.21 % | 0.19 % |
| MgO | 5.2 % | 5.31 % | 9.63 % |
| CaO | 6.43 % | 11.18 % | 13.05 % |
| Na2O | 2.91 % | 3.92 % | 2.21 % |
| K2O | 0.36 % | 1.73 % | 0.72 % |
| TiO2 | 2.9 % | 3.98 % | 5.27 % |
| P2O5 | 0.53 % | 1.07 % | 1.77 % |
| LOI | 6.7 % | ||
| FeO | 10.4 % | 15.86 % | |
| Total: | 99.77 % | 98.83 % | 98.24 % |
Sample references:
| ID | Locality | Reference | Notes |
|---|---|---|---|
| 1 | Sierra La Vasca alkaline complex, Ocampo Municipality, Coahuila, Mexico | Martínez-Salinas, Edgar A.; Weber, Bodo; Díaz-Martínez, Roberto; Padilla-Ramírez, Sergio; Frei, Dirk (2025) Petrogenetic characterization of La Vasca alkaline complex and its relationship to the Eastern Mexican Alkaline Province. Journal of South American Earth Sciences, 164. p.105674. doi:10.1016/j.jsames.2025.105674 | Bulk rock analyses was perfromed by WD-XRF spectrometry on a crushed sample from a gabbro dike containing kali-feldspar, pyroxene and amphibole as the main minerals. |
| 2 | Mont Royal, Montréal, Québec, Canada | Wet chemical analysis by G. Woussen and B.M.Gunn. The Fe2O3 percentage is arbitrarily set to 2% | |
| 3 | " " | Wet chemical analysis by G. Woussen and B.M.Gunn. The Fe2O3 percentage is arbitrarily set to 2%. |
Synonyms of Gabbro
Other Language Names for Gabbro
Irish Gaelic:Gabró
Common Associates
Associations Based on Photo Data:
| 7 photos of Gabbro associated with Plagioclase | (Na,Ca)[(Si,Al)AlSi2]O8 |
| 6 photos of Gabbro associated with Pyroxene Group | ADSi2O6 |
| 4 photos of Gabbro associated with 'Diallage' | |
| 3 photos of Gabbro associated with Quartz | SiO2 |
| 2 photos of Gabbro associated with Epidote | (CaCa)(AlAlFe3+)O[Si2O7][SiO4](OH) |
| 2 photos of Gabbro associated with Laumontite | CaAl2Si4O12 · 4H2O |
| 2 photos of Gabbro associated with Pyrite | FeS2 |
| 1 photo of Gabbro associated with Diopside | CaMgSi2O6 |
| 1 photo of Gabbro associated with Calcite | CaCO3 |
| 1 photo of Gabbro associated with Amphibole Supergroup | AB2C5(T8O22)W2 |
Internet Links for Gabbro
mindat.org URL:
https://www.mindat.org/min-48275.html
Please feel free to link to this page.
Please feel free to link to this page.





Bosspruit quarry, Rustenburg, Rustenburg Local Municipality, Bojanala Platinum District Municipality, North West, South Africa