Updates prices and details throughout

By Tharuniyaa Lakshmi

May 25 (Reuters) - Canada's main stock index rose to a record high on Monday, led by gains in materials stocks as investors took comfort from signs that the United States and Iran were negotiating an end to their conflict.

At 10:21 a.m. ET (1421 GMT), the Toronto Stock Exchange's S&P/TSX composite index .GSPTSE was up 0.7% at 34,778.98 points.

• U.S. President Donald Trump said on Saturday a peace deal had been “largely negotiated” that could reopen the Strait of Hormuz. However, both parties played down hopes for an imminent breakthrough in their three-month-old war, keeping gains in check.

• "There have been repeated false hopes of a resolution, but this is how markets trade ... even a non‑zero chance the conflict ends is enough to push stocks higher and oil lower, though we’re not 100% convinced this is the real deal," said Brian Madden, chief investment officer at First Avenue Investment Counsel.

• The heavyweight mining stocks .GSPTTMT led gains, up 3.1%, as gold prices rose, helped by a weaker U.S. dollar and easing inflation concerns. GOL/

• Aya Gold and Silver AYA.TO, Hudbay Minerals HBM.TO and Americas Gold & Silver USA.TO were all up more than 5% and were among the top movers on the benchmark index.

• Nine of 10 sectors in the TSX edged higher, while energy stocks .SPTTEN were the only laggard, falling 2.1%, tracking a 5.7% slide in U.S. oil prices to $91 a barrel. O/R

• The index surpassed its March 2 peak on Friday to hit a record high.

• Quarterly results from major banks, including Royal Bank of Canada RY.TO, Toronto-Dominion Bank TD.TO and Bank of Montreal BMO.TO, among others, are expected later this week.

• The financials sector .SPTTFS has gained the most among sectors in May, up 5.5%.

• Investors and businesses will also be keen on the first round of formal negotiations of the U.S.-Mexico-Canada free trade deal that is expected to kick off in Mexico on Monday.