March 19 (Reuters) - The mainstream quotation range for xylene in the South China market is 7,650–7,800 yuan/ton, down 10 yuan/ton from the previous trading day. In the previous trading session, toluene and xylene prices rose slightly, with significant support from cost and supply-side factors. Ongoing geopolitical tensions in the Middle East have kept energy prices elevated, coupled with expectations of tightening domestic spot resources, leading to firm supplier offers and increased reluctance to sell. However, downstream buyers remain cautious and risk-averse, with limited follow-through in spot transactions, constraining further upward price momentum. The market is expected to experience high volatility during the day, with a focus on actual transaction volumes and changes in downstream purchasing patterns.