Mining stocks didnt join in with the post-Scottish referendum euphoria on Friday with share prices in the sector down an average 0.6% in afternoon trade.A broad sell-off of commodity prices was weighing on stocks during the session, with gold in particular trading near an eight-month low as the dollar advanced on Federal Reserve interest-rate speculation. Gold was down for a third straight week and futures for December delivery hit a low of $1,216.30 on Thursday, its lowest since 6 January.The drop in the price of bullion meant that precious metal miners Randgold Resources and Fresnillo were trading firmly in the red.Silver, platinum and copper prices were also weaker on Friday.Meanwhile, ratings agency Moody's had dampened sentiment after warning that credit ratings of miners could be under threat from a fall in the price of iron ore.There were also growing concerns that a potential nationalisation of the Russian oil industry could spread to the metals and minerals market.According to analysts at Investec, there are fears that the idea of nationalising Russian oil "will inevitably flow on to the mining and metals sector given the importance of companies such as Norilsk to global copper, platinum group metals and nickel supply".Other blue-chip miners such as Rio Tinto, Anglo American and BHP Billiton were also unwanted on Friday. Top performing sectors so far todayIndustrial Metals & Mining 1,602.83 +2.38%Real Estate Investment Trusts 2,902.20 +1.65%Electronic & Electrical Equipment 3,771.39 +1.62%Oil Equipment, Services & Distribution 22,618.38 +1.61%Insurance (non-life) 1,899.09 +1.55%Bottom performing sectors so far todayConstruction & Materials 3,952.94 -1.07%Mining 16,704.94 -0.64%Household Goods & Home Construction 12,191.50 -0.47%Chemicals 10,174.89 -0.38%Personal Goods 24,270.44 -0.32%