The c. 1.89 Ga Garpenberg Zn-Pb-Ag-(Cu-Au) deposit is hosted by dolomite marble, skarn and felsic metavolcanic rocks. Extensive marble units host part of the mine infrastructure, including sections of bright-colored, chemically pure marble. Assessing the potential of carbonates as by-products to base metal mining is of interest for a sustainable and efficient use of resources and for securing a domestic supply of carbonates. This study characterizes marble units proximal to the Dammsjön and Lappberget ore bodies at Garpenberg based on their optical, chemical, mineralogical, and textural properties to delineate controls on their brightness, color, and purity. Methods employed include drill core logging, whole-rock lithogeochemistry, petrography, SEM-EDS, μXRF, spectrophotometric brightness measurements, and tests of AIR and magnetic separation. The marble units are divided into bright calcite marble (white, gray, and green varieties), dark calcite marble (salmon pink, spotted, brecciated, and ophicalcite varieties) and dolomite marble. Brightness and purity of the marbles are highly correlated, with Fe having a particularly detrimental effect on brightness, both via substitution in the dolomite and calcite lattices, but also via presence of accessory minerals that grind to dark powders. Ore-proximal dolomite marble shows a hydrothermal signature, with elevated base metals, Fe, S and Mn content, whereas impurities in calcite marble seem to mainly be of detrital origin, reflecting co-settled volcaniclastic and siliciclastic material in the limestone precursors. Mainly the bright calcite marble varieties are of potential industrial quality and are present in Garpenberg in significant volumes, but the technoeconomic feasibility of by-product valorization requires further analysis.