Ignoring warnings from his friends Saturday night that it was too dangerous to try to spray-paint his name on the sheer face of the Lorton quarry, 18-year-old Mark A. Cicioni of Woodbridge tied one end of a 20-foot rope around a tree, held onto the other end, "swung out over the edge and it snapped," a Fairfax County police officer said yesterday.

Cicioni's body was recovered Sunday in 10 feet of water in the mined-out quarry. Two friends who had been with him when he plunged about 100 feet to his death told police the three crawled through a fence into the quarry, intending to spray-paint their names on the cliff, according to Lt. Daniel J. Kerr.

But the friends -- a 17-year-old Woodbridge resident and classmate of Cicioni's at Woodbridge High School and his 21-year-old brother -- said they decided the escapade was too dangerous when they reached the top of the cliff, Kerr said.

"They said they had tried to talk him out of swinging over the edge there . . . but the Cicioni boy said he wanted to do it," said Kerr, who supervised the search Saturday night and Sunday morning for Cicioni's body.

The rope was an old, hemp rope, about 1 1/2 inches thick, that appeared to have been weakened by dry rot, Kerr said.

Police would not release the names of Cicioni's companions, saying that the brothers were too distraught to discuss the incident.

They said the brothers could be charged with trespassing but that it was unlikely. "Generally, in a tragedy like that, unless there's some real reason to go back and charge them," police do not bring charges, Kerr said.

"It seems like the boys love to take risks: if there's anything dangerous they love to do it," said Lucy Hasselvander, Cicioni's guidance counselor at Woodbridge High School. "He didn't impress me as that kind of person, but boys are just daredevils. They think they can't get hurt."

Cicioni, who was in his senior year, was "just a real sweet boy . . . . He always thanked me and thanked me when I would talk to him" about his future plans.

Cicioni's family, who made funeral arrangements yesterday for services tomorrow at Our Lady of Angels Church in Woodbridge, declined to speak to a reporter.

The property, in southern Fairfax County off Rte. 123 near the Prince William County line, is owned by the Fairfax County Water Authority, which uses the quarry as a dump for waste water from the purification process, according to water authority spokesman James Warfield.

Fairfax County police said the quarry was operated by the Vulcan Materials Co., but company spokesman Jerry Simmons said the Huntsville, Ala.-based firm stopped mining there in 1980.

Warfield said that the site was surrounded by an eight-foot chain-link fence topped with barbed wire, and that a security guard was on duty in the evenings.

But "barring stationing people around the perimeter of the quarry 24 hours a day there's not much you can do to keep someone out who's determined to get in," he said.