The correct answer is Diamonds
Maritime trade was of great importance in the Roman world. The Empire's economy was based on a single currency, a collection of customs duties and a network of protected roads and ports. All of this to facilitate trade between the various regions.
Through trade, an important cultural bridge was created between the Roman Empire and other civilizations around the world. The Romans had several manufactures whose production was strongly linked to foreign markets, both within and outside imperial limits.
Glass and perfumes made in Syria and Egypt were sold in the Near East to Greek, Latin, Indian, childbirth and even Chinese merchants occasionally. These products were taken to all the provinces of the empire, where they were used by the local elites as symbols of ostentation, prestige and civilization. This social practice, also found in China, India and Parthia, gave rise to the import of these luxury goods, which reached excellent prices outside the Empire.
