Is Basalt the Best Source for Garnet?

Why is basalt not considered the best source for garnet?

Basalt is a good source of garnet but not the best. Granite can be a better source for it.

Answer:

Basalt is not typically considered a primary source of garnet. Garnet is a mineral that occurs in a variety of rock types, including metamorphic rocks like schist and gneiss, as well as some igneous rocks like granite. While it is possible for garnet to occur in basaltic rocks, it is not the most common or abundant source.

Basalt, a common type of volcanic rock, is known for its unique mineral composition and textures. Olivine, pyroxene, and plagioclase are the major minerals that makeup basalt, which is abundant in iron and magnesium. The majority of specimens have a glassy, compact, fine-grained texture. Additionally, they may contain plagioclase, augite, or olivine phenocrysts and be porphyritic. Basalt may have a coarsely porous texture due to gas bubble-induced holes.

The metamorphic rocks are where you'll find the garnets that make rocks. Particularly in granite and granitic pegmatite, which occur in igneous rocks. Clastic sediments and sedimentary rocks occasionally contain garnets that were formed from such rocks. The primary type of rock used to make cogged stones, basaltic scoria, is made from magmas that effusively erupt at the surface as lava flows and are mostly generated from various regions of the Earth's mantle or lower crust.

The most significant sources of garnet are often associated with metamorphic processes, where the mineral can crystallize and grow within specific temperature and pressure conditions. Garnet can also be found in placer deposits, which are accumulations of minerals in sedimentary environments like riverbeds and beaches, where erosion has concentrated heavy minerals like garnet.

If you are specifically looking for sources of garnet, it's more common to find it in rocks like schist, gneiss, and certain types of sedimentary rocks, rather than basalt. However, the presence of garnet in any rock type depends on the geological history of the region.