How much gold you can borrow varies from lender to lender and the purity of the gold pledged.  Gold accepted as collateral should be of 18k purity, 22k purity or 24k purity. Typically you can get up to 60-70% of the value of the gold you have pledged.

However each bank or NBFC has their own policies regarding disbursal of loan, and the loan amount disbursed is solely under the discretion of the lender.