Energy prices were rising Thursday on hopes that an improving global economy will boost demand for petroleum products, but precious metals were losing some of their crisis-fighting attractiveness owing to the same expectations of a recovery. Crude oil for May delivery recently was up $3.46 at $51.85 a barrel, and reformulated gasoline was adding 8 cents to $1.46 a gallon. Heating oil was also up 8 cents, at $1.43 a gallon, while natural gas was fractionally better at $3.70 per million British thermal units. Gold and silver, meanwhile, were tumbling. Gold was recently down $23.20 at $904.50 an ounce, and silver was losing 19 cents to $12.79 an ounce. Copper was up 4 cents at $1.89 a pound. Agricultural futures were stronger across the board, led by wheat, soybeans, cocoa and sugar. Lean hogs and cattle were also advancing. The Reuters/Jefferies CRB Index was higher by 5.51 points at 223.32. In the foreign-exchange market, the dollar was plunging against most of its major counterparts, and both the euro and the pound rose roughly 2% on the greenback. The yen, however, was weaker. As for commodity-related stocks, Chevron ( CVX) was up 3.9% at $70.98, and Exxon Mobil ( XOM) was adding 2.2% at $70.72. Gold miners were falling. Agnico-Eagle ( AEM) was down 6.7% at $53.97, Eldorado Gold ( EGO) was off 3.8% at $8.79, and Barrick Gold ( ABX) was losing 4.5% to $32.37.