A granite block slated to fill a hole in Weld Hall disappeared from the dorm's reconstruction site on January 9, the general contractor said yesterday.

John A. Thomas, the general superintendent of Beacon Construction, said it is possible that someone might have taken the block under the mistaken impression that it was junk.

Thomas said he does not suspect foul play. But the block is "a precious commodity," according to Peter J. Riley of Harvard Real Estate, the manager of the Weld renovation. The 19th century granite used to construct Weld is very hard to match, Riley said.

The renovators are trying to maintain the original integrity of Weld, he said.

"We've worked really hard to maintain the original fabric of the building. It is one of the main things that guides our work," Riley said.

The contractor had originally planned to discard the block because the hole was going to hold a fire hose. But when the fire department ordered the location of the hose changed, the block was nowhere to be found, Thomas said.

Riley said that if the block is not found, the hole will be filled with similar-looking granite. The difference in granite will not be noticeable since that part of the building will be covered by shrubbery in any case, he said.

Students currently living in Matthews Hall are scheduled to move into Weld at the end of this semester.