The Compostela Hyacinth is a variety of red quartz, also known as hematoid quartz, whose reddish color is due to iron oxide inclusions. It was named by pilgrims on the Camino de Santiago (Way of St. James), who collected it as a souvenir in the regions where it was found. It is characterized by its trigonal crystal system and its formation in Triassic deposits, often on a red gypsum matrix.