goldsmith is not covered under specified professions so, he is liable to pay tax under presumptive taxation scheme, if his total turnover / gross receipts of upto rs 200 lakh (2 crore )[section 44AD]
yes, you are not required to maintain books of accounts u/s 44AA or get them audited u/s 44AB (if you are eligible for section 44AD) presumptive rate of tax would be 8% of total turnover or gross receipts it can reduce to 6% of total turnover or gross receipts if all the transactions made through 1. by an account payee cheque OR 2. by an account payee bank draft OR 3.by use of electronic clearing system through a bank account
on the above, tax liability is calculated as per your slabe rate