Finding-sites of characteristic spanish minerals can be found in the 'Keuper', a sediment layer between 235 million to 200 million years old. Fre floating in the sediment formed crystals of aragonite and quartz - intense red coloured ”Hämadoite” (so called "Hyacinth of Compostela") can be found there. The here shown globular crystallized aggregate comes from Chella in the province of Valencia.

In addition to these macroscopically crystallized minerals sometimes chalcedony in nodular aggregatesdoes occur too. The specimen shown here comes from Azuella, located between Merida and Zaragoza.