A fluctuating solution to the dolomite problem

Episodes of dissolution and crystal growth stoke the formation of a common carbonate mineral The impressive massif of the Dolomite Mountains in Northern Italy was formed almost entirely of CaMg(CO 3 ) 2 , a calcium-magnesium carbonate mineral discovered in 1791 by the French naturalist Déodat de Dolomieu ( 1 ), who gave name to both the mineral—dolomite—and to the impressive Alpine rocky landscape considered by the architect Le Corbusier as “the most beautiful architectural work in the world” ( 2 ). Although abundant in ancient sedimentary rock, its rarity in modern environments has puzzled geologists for more than a century. Indeed, tackling this mystery in laboratories has proven formidable, hindering the study of this mineral—the so-called “dolomite problem.” On page 915 of this issue, Kim et al. ( 3 ) demonstrate that cycles of saturation conditions promote dolomite crystal growth in the laboratory. This discovery opens the door to investigating the geochemical process that influenced massive dolomite formation in the natural world.