Gold prices turned weak at the bullion market here today on slackened demand from jewellers and retailers even as the metal strengthened overseas. Silver, too, declined by Rs 70 per kg -- a sign of softness in orders from industrial units. Standard gold (99.5 per cent purity) fell by Rs 30 to finish at Rs 31,295 per 10 grams from Wednesday's closing level of Rs 31,325. Pure gold (99.9 per cent purity) also moved down by the same amount to close at Rs 31,445 per 10 grams from Rs 31,475 earlier.