Joe Esposito writes:

Since 1901, the Nobel Prize medals have been part of many remarkable stories. Three Nobel medals had to be dissolved in Denmark to keep them hidden from the Nazis. Two Nobelmedals were mixed up between different laureates and it subsequently took them four years to correct the mistake. One Nobel medal caused confusion at airport security as it turnedup completely black in the X-ray machine in Fargo, North Dakota. This is, to say the least, a very special gold medal.

In 1902, the Laureates received the first "real" Nobel Prize medals for Physics, Chemistry, Physiology or Medicine and Literature designed by the Swedish sculptor and engraverErik Lindberg. Then you might ask why not since 1901, when the first Prizes were awarded? The reason for the delay was because the designs of the reverse sides of the "Swedish"Nobel medals were not finalized in time for the first Award Ceremony in 1901. The designs needed to be approved by each Prize-awarding institution.

From Erik Lindberg's correspondence with his father Professor Adolf Lindberg, it seems as if each of the 1901 Laureates received a "temporary" medal - a medal bearing theportrait of Alfred Nobel, struck in a baser metal - as a memento until the "real" medals were finished. The first of these medals were not completed and struck until September1902.

See how the Nobel Medals are manufactured

To read the complete articles, see:
A unique gold medal(https://www.nobelprize.org/prizes/about/the-nobel-medals-and-the-medal-for-the-prize-in-economic-sciences/)
A work of art in the form of a diploma (https://www.nobelprize.org/prizes/about/the-nobel-diplomas)