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Skarn deposits are one of the more abundant ore types in the earth’s crust and form in rocks of almost all ages. Skarn is a relatively simple rock type defined by a mineralogy usually dominated by calcsilicate minerals such as garnet and pyroxene. Although the majority of skarns are found in lithologies containing at least some limestone, they can form in almost any rock type during regional or contact metamorphism and from a variety of metasomatic processes involving fluids of magmatic, metamorphic, meteoric, and/or marine origin. Although most are found adjacent to plutons, they also can occur along faults and major shear zones, in shallow geothermal systems, on the sea floor, and at lower crustal depths in deeply buried metamorphic terranes. Thus, neither a pluton nor limestone is necessarily required to form skarn. Most skarn deposits are zoned, and the general pattern is proximal garnet, distal pyroxene …