Gold prices on Monday marginally declined by Rs12 to Rs72,978 per 10 grams in futures trade as speculators reduced their positions. On the Multi Commodity Exchange, gold contracts for August delivery traded marginally lower Rs12 or 0.02 per cent at Rs72,978 per 10 grams in a business turnover of 10,689 lots. Analysts attributed the fall in gold prices to weak global cues.