Positively charged nanosheets with a lateral dimension of micrometers have been synthesized by directly delaminating a well-crystallized Mg−Al layered double hydroxide (LDH) in the nitrate form. The action of formamide on LDH crystals 10 μm in size led to a transparent solution. X-ray diffraction measurement on a glue-like colloid centrifuged from the solution detected a broad feature at small angular range, while completely losing the sharp reflections for the precursor crystalline compound. The broad profile was very similar to the square of the structure factor calculated based on the LDH structure, which provides strong evidence for the total exfoliation of the LDH crystals into their single sheets. Upon in situ aging in a stream of nitrogen gas, the broad pattern was gradually converted into a sharp basal diffraction pattern, indicating the restacking of molecular LDH nanosheets to restore the original stacked form. Observations by transmission electron microscopy and atomic force microscopy revealed...