Rock crystal, imported from Venice and highly valued for its rarity and symbolic value, was another material that grew in popularity in the Middle Ages. After the slabs of rock crystal had been lapidated and polished they were set or combined with a precious metal thus creating a luminosity difficult to equal. On this cross, from the Convento de Santa Clara, two miniatures, representing the Crucifixion and the Slumber of the Virgin, hide the intersection of the bars of the cross