GARNET (SPESSARTINE), BROKEN HILL, NSW, AUSTRALIA

Garnets are a category of silicate minerals that have been utilized as gemstones and abrasives since the Bronze Age. While all garnet species share similar physical characteristics and crystal structures, they vary in their chemical compositions. The main types include pyrope, almandine, spessartine, grossular (which includes varieties such as hessonite or cinnamon-stone and tsavorite), uvarovite, and andradite. Garnets are classified into two solid solution series: the pyralspite series, comprising pyrope, almandine, and spessartine with the formula [Mg,Fe,Mn]3Al2(SiO4)3, and the ugrandite series, which includes uvarovite, grossular, and andradite with the formula Ca3[Cr,Al,Fe]2(SiO4)3.