Protodolomite associated with Miocene palygorskite deposits of Georgia and Florida provides a clue as to how some euhedral dolomite crystals are formed. The early dolomite has a frothy texture and is formed of plates, sheets, and fragmental rhombs; with time the number of crystal faces increases, and euhedral dolomite crystals form. The dolomite grew slowly from dilute water in a schizohaline environment. The dolomite crystals were constructed layer by layer and face by face. When the supply of Mg decreased, construction ceased, thus preserving the intermediate morphologic types.