Sorted GarnetsThis is kinda neat. This is a pile of sand-sized grains of garnets, originally from Ne

Sorted GarnetsThis is kinda neat. This is a pile of sand-sized grains of garnets, originally from New Mexico. The grains started out in one of several large areas of precambrian-aged metamorphic rocks exposed in the area; these rocks originally were metamorphosed as the continent Laurentia – today forming the bulk of North America – was growing by collisions with other continents and island arcs. Those ancient rocks are now exposed at the surface today, where they are eroding and shedding sediments into nearby lowlands.This sand was first sorted and kicked up by ants, while they were building hills out of sand grains. Then, to isolate the garnets from everything else, a strong rare earth element magnet was moved over the sample. While garnet isn’t a strongly magnetic mineral, if put in a powerful enough magnetic field garnet can be sorted from other minerals.Garnet commonly forms complex, high-symmetry shapes like dodecahedrons, along with some hexoctahedrons and trapezohedrons. Although some of the faces either were worn off by erosion or maybe never formed as perfect faces in the first place, you can definitely see some of the dodecahedral patterns in these grains.-JBBImage credit: https://flic.kr/p/9737SUReferences:https://geoinfo.nmt.edu/publications/monographs/bulletins/downloads/53/Bulletin53.pdfhttps://www.gemstonemagnetism.com/understanding_garnets_through_magnetism.html -- source link

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