Bolinus brandaris, commonly known as the purple dye murex, is a marine gastropod mollusk found in the Mediterranean Sea and the eastern Atlantic Ocean. This species is notable for its role in ancient dye production, particularly the famous Tyrian purple, which was highly valued in antiquity. The murex has a distinctive shell with spiny projections and can grow up to 10 centimeters in length. The purple dye is extracted from a gland in the murex, requiring thousands of snails to produce just a small amount of dye. This labor-intensive process made Bolinus brandaris and its dye a symbol of wealth and status in ancient cultures, including the Phoenicians and Romans. Today, the species is protected in many areas due to overharvesting and habitat loss.