Čechite, a rare vanadate from the Ulldemolins mines (Catalonia)

Čechite is a very rare lead and iron hydroxylvanadate, with the formula PbFe²⁺(VO₄)(OH), which has been found in very few localities worldwide. The first world location in which it was determined was in the Vrančice mines, in the Czech Republic, in the early 1980s. It has subsequently been found in Italy and the United States. It has no industrial interest, despite the fact that vanadium is a strategic element, since this mineral occurs in small quantities. 

This species usually appears as small tabular to equidimensional crystals, with a black color and a resinous to submetallic luster. The best crystals known until recently were those of the Czech Republic.

A find on the beach

The shells or shields on the back of the various species of cuttlefish Sepia spec. consist of brittle lime (sometimes also referred to as Sea Foam) and are softer on one side than on the other. There is gas between the layers of lime, so that they float and often wash up on the beach.

Cuttlefish are good swimmers who can cover large distances. Sometimes animals wash ashore on the coast, but more often loose back shields. They have good buoyancy and can wash up on the beach at a great distance from the place where the animal died.