The specimens that we often see on the market as sylvite or carnallite are usually halite with inclusions of iron minerals. In this case, the specimen has been analyzed indicating that it is mainly sylvite (KCl) with some halite (NaCl) included. The red color is due to inclusions of iron oxydes (hematite). Although it is a salt long exploited in these mines in the Catalan potassium basin, it is a mineral that is sometimes missing from collections.