During the start of the Silk Road, the Roman Empire controlled much of Europe while also conquering Egypt and the Parthian Empire controlled the Middle East.

This gave the Chinese access to fabrics (wool, cotton, tapestries, carpets), seeds (I believe it was during this time that the Chinese were exposed to grape wine), resin (frankincense, myrrh), horses (larger and stronger than the ones bred within China), and glass (from Egypt).

Later on, during medieval times, you had the Eastern Roman Empire and Second Persian Empire, although most of the commodities traded during this time were very much the same as before. One thing to note is that across the Silk Road, much more was 'traded' other than items. Religion (Islam, Buddhism, Christianity) and culture (music, dances, ways of life) were also transmitted from West to East and vice versa.

Edit: Realised that I should be adding sources.

A Modern Chinese Journey to the West, Economic Globalisation and Dualism - Killion, M. Ulric

Old World Encounters: Cross-Cultural Contacts and Exchanges in Pre-Modern Times - Bently, Jerry

The Silk Road, in the series of Essays on Global and Comparative History - Liu, Xinru

Here in Korea, there are examples of Roman(style) glassware (bowls and cups), along with glass and ceramic beads. Some of the beads are incredible in that the material that made them up was layered in such a way to create images of animals and faces. Most of the glassware and all of the beads were excavated from royal tombs, so I would assume it was considered quite precious.

The Romans paid in silver specie for their massive imports of silk during the Empire. This drainage of silver didn't go unnoticed among the Roman elite and was a huge source of controversy as it contributed among other things to the debasement of the currency and the gradual loss of confidence in the coinage in the banking sector and the military recipients of the coinage. All this for the import of a luxury item.