A method for fabricating calcite channels in a nanofluidic device is described. A photoresist layer is coated onto a top surface of a silicon nitride (SiN) substrate. After coating the photoresist layer, the photoresist layer is scanned with an electron beam in a predefined pattern. The scanned photoresist is developed to expose portions of the top surface of the SiN substrate in the predefined pattern. Calcite is deposited in the predefined pattern using atomic layer deposition (ALD) using a calcite precursor gas. Using a solvent, a remaining portion of the photoresist layer is removed to expose the deposited calcite in the predefined pattern and on the top surface of the SiN substrate, where a width of the deposited calcite is in range from 50 to 100 nanometers (nm).