Mole Day is an unofficial holiay celebrated among chemists in North America on October 23, between 6:02 AM and 6:02 PM, making the date 6:02 10/23 in the American style of writing dates. The time and date are derived from the Avogadro constant, which is approximately 6.022×1023, defining the number of particles (atoms or molecules) in a mole, one of the seven base SI units.