A D.C. Superior Court judge sentenced a Washington antiques dealer yesterday to spend up to six years in jail for using a scheme to defraud many of her customers out of hundreds of thousands of dollars worth of their personal property.

Dolores M. Mason, 50, who operated Mason Antiques Inc., at 2651 Connecticut Ave. NW, pleaded guilty in March to one count of grand larceny after trust and to one count of writing a bad check.

Judge Donald Smith sentenced Mason to a jail term of from one to six years for grand larceny in connection with a June 1978 transaction in which she sold a customer's $9,000 diamond ring for $4,500 and kept the proceeds of the sale.

In addition, the judge sentenced Mason to from one to three years for intentionally writing a bad check to a customer for $1,622,75, when she did not have sufficient funds in her bank. The sentence in that case was suspended and Mason was placed on probation on that charge.

During the 21 months Mason was in business, she defrauded at least 51 persons out of more than $300,000 worth of antique furniture, art objects and articles of jewelry left at her shop to be sold on consignment, according to evidence in court records.

Mason, of 4218 Robertson Blvd., Alexandria, wrote $59,684.30 worth of bad checks to customers who thought they were being paid for articles that Mason had sold, according to these records.