On March 5, 2018, in Události, The Czech Television informed about the fact the server Hlídací pes had come up with that there was a piece of glass instead of the 3rd largest diamond and a synthetic sapphire instead of the natural one in the National Museum’s gemstone collection. There were a few odd facts. The new curator of the collection, Lukáš Zahradníček, was surprised to find that these problems had been coming out in the last few years and at the same time he stated that a half of the rubies in the collection were synthetics.The management of the National Museum has been wondering how this could happen. The two previous curators of the collections were experts. One should be stunned that the museum management has long been investigating whether the stones are perhaps stored elsewhere. They tried to find out if there had been any confusion of incompetence. Here, we can say that this direction of the investigation is completely wrong. It is clear that an unqualified purchase, fraud during the purchase or fraudulent replacement-theft in the collection have happened. The case does not have to be time-barred, due to the fakt no one knows when the replacement took place! This case showed how important is the morality of the curators of the collections and their inspection. At the National Museum, the inspection was obviously neglected!