PORTLAND, Ore. (AP) _ NASA stopped short of determining whether a desk set it seized from an Oregon woman contained valuable moon dust as suspected and quietly returned the family heirloom, the woman said Tuesday.

The black base of the pen-and-pencil set is adorned with a faded picture of the Apollo 11 moon landing, with a centerpiece of a yellow plastic rock containing dusty swirls.

The set was given to Peg Davis by her late father, Joe Healy, upon his retirement as a scientist at NASA. The agency seized it about a month ago, alleging that Davis was either trying to defraud the public or was illegally trying to sell NASA property.

Davis caught NASA's attention when she had the desk set appraised for possible sale. She appeared Tuesday on the ``Today'' program to say NASA had tested the set and was unable to determine whether it contained moon dust, so they gave it back.

``They said they looked at it through a microscope, and to be able to tell whether it was moon dust, they'd have to melt it down and do more intrusive testing, which would in essence destroy what it is,'' she said.

Although lunar rocks have been given to foreign governments as goodwill gifts, private ownership is not permitted.

After her father's death, Davis wanted to give the set to a museum, until she learned its potential value. A New York antiques dealer estimated the item's worth at about $1 million. The dealer inadvertently tipped off NASA when he called the agency with a question about the set.

Davis said she hasn't decided what she will do with the set.