Carnalite (KMgCl3·6H2O, hydrous magnesium and potassium chloride) from Cardona. Carnalite crystallizes in rhombic system and has a hardness of 2.5, the same as the nail. It usually displays granular structure. Carnalite can be colorless, pinkish or reddish, always with a vitreous gloss. Carnalite is deliquescent, it solves even in the air humidity. Its taste is salty, spicy after the potassium and bitter after the magnesium content.
In the sequence of the Cardona geological pack, carnalite is found in a higher position than silvine. Thus, carnalite is the first potassium mineral that appears, however its presence is irregular.
[photo Joaquim Sanz / Museum of Geology Valentí Masachs]